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KATSUI Tokihiro
Ocean-Bottom Exploration Center (KOBEC)
Professor

Researcher basic information

■ Research Keyword
  • Ship Performance
  • 船舶抵抗推進性能
■ Research Areas
  • Aerospace, marine, and maritime Engineering / Marine and maritime engineering
■ Committee History
  • The Kansa Society of Naval Architects, Japan, member, The Kansa Society of Naval Architects, Japan
  • The Society of Naval Architects of Japan, member, The Society of Naval Architects of Japan
  • 関西造船協会, 正会員, 関西造船協会
  • 日本造船学会, 正会員, 日本造船学会

Research activity information

■ Award
  • May 2000 関西造船協会, 関西造船協会賞, 重力影響を考慮した滑走艇の未定浸水面問題に関する変分原理について
    KATSUI Tokihiro, MATSUMURA Kiyoshige

  • 2000 The Kansai Society of Naval Architects, Japan Prize

  • May 1999 日本造船工業会, 日本造船工業会賞, 滑走艇の未定浸水面問題に関する変分原理について
    MATSUMURA Kiyoshige, KATSUI Tokihiro

  • May 1999 日本造船学会, 日本造船学会賞, 滑走艇の未定浸水面問題に関する変分原理について
    MATSUMURA Kiyoshige, KATSUI Tokihiro

  • May 1999 日本財団, 日本財団賞, 滑走艇の未定浸水面問題に関する変分原理について
    MATSUMURA Kiyoshige, KATSUI Tokihiro

  • 1999 The Society of Naval Architects of Japan Prize

■ Paper
  • Investigation of Coating Roughness Effects in Ship-scale CFD
    Shun Kuwahara, Kunihide Ohashi, Ryo Nishioka, Tokihiro Katsui
    Corresponding, May 2025, 日本船舶海洋工学会講演会論文集, (40) (40), 437 - 448, Japanese, Domestic magazine
    Scientific journal

  • Evaluation of Full Scale Ship Performance Based on Low Re Model CFD Considering Painted Surface Roughness
    Ryo Nishioka, Kunihide Ohashi, Nobuaki Sakamoto, Shun Kuwahara, Riku Sato, Tokihiro Katsui
    Corresponding, May 2025, 日本船舶海洋工学会講演会論文集, (40) (40), 427 - 436, Japanese, Domestic magazine
    Scientific journal

  • Tomoki Wakabayashi, Tokihiro Katsui
    The Hybrid Contra Rotating Propeller is a developing propulsion system that combines a conventional single-shaft propeller with a POD propeller to achieve high energy-saving performance through a Contra Rotating Propeller. In this paper, a new towing tank test method for the Hybrid Contra Rotating Propeller was suggested. By conducting seven patterns of propeller open-water tests and measuring the individual propeller performance and the interaction between the propeller and the POD, the propeller’s mutual interaction can be obtained. Towing tank tests for a study ship were conducted, and the analyzed results are shown. There exists the effect of the wake of the propeller open boat at an unusual (reversed) test layout, which simulates the Hybrid Contra Rotating Propeller, and this effect must be removed for the accurate estimation of the ship’s performance. In conventional towing tank test methods, this effect on the front propeller was obtained and used to correct the performance of the total unit of the Hybrid Contra Rotating Propeller. The presented method allows for the correct removal of the open boat effect on the performance of each propeller and the propeller mutual interaction, resulting in more accurate power estimation. Furthermore, by using the individual performance of two propellers and interaction terms, the presented method enables us to conduct a power estimation at an arbitrary revolution rate of two propellers.
    MDPI AG, Apr. 2025, Journal of Marine Science and Engineering, 13(5) (5), 858 - 858, English, International magazine
    [Refereed]
    Scientific journal

  • Tatsuya Kaneko, Tomoya Inoue, Ryota Wada, Tokihiro Katsui, Hiroyoshi Suzuki
    Abstract Understanding drill string dynamics is essential to improving drilling efficiency and preventing accidents. Previous studies have mainly focused on self-excited oscillations due to stick–slip and bit-bounce. However, in deepwater drilling, large weight-on-bit (WOB) fluctuations due to heave motion are a significant concern that can affect torsional dynamics. This article reports analytical, numerical, and field data investigations on torsional vibrations of a drill string in deepwater drilling. First, we analyzed the field data from a deep-sea scientific drilling vessel Chikyu. The field data showed that heave, WOB, and torque oscillated at similar frequencies. This result indicated that the drill string could have forced torsional vibrations due to heave instead of self-excited vibrations due to stick–slip. Second, we analytically and numerically investigated drill string torsional dynamics. The torsional vibration of the drill string can be described only by self-excited vibration due to stick–slip if WOB is constant. However, when the WOB fluctuates, the forced vibration of the WOB must be considered. The results showed that vibration at the heave frequency had a more significant effect on torsional vibration than the axial self-excited frequency for the same amplitude of WOB variation. In addition, large WOB fluctuations increased the risk of stick–slip and reverse rotation of the drill bit. Numerical experiments with the field data showed that the forced torsional vibration caused by heave motion was predominant in deepwater drilling. These results show the importance of capturing forced torsional vibrations and reducing WOB fluctuations.
    ASME International, Mar. 2025, Journal of Offshore Mechanics and Arctic Engineering, 147(6) (6), English, International magazine
    [Refereed]
    Scientific journal

  • Equivalent Sand Roughness at Actual Ship Scale CFD
    Ryo Nishioka, Tokihiro Katsui, Shun Kuwahara, Riku Sato, Hirohisa Mieno
    Corresponding, Nov. 2024, 日本船舶海洋工学会講演会論文集, (39) (39), 1095 - 1104, Japanese, Domestic magazine
    Scientific journal

  • Correlation between Hydrodynamic Force Behavior and Displacement Volume Distribution of Lateral Motion Ships at Shallow Water
    Takuro Adachi, Shigeru Nishio, Kenichi Takamatsu, Tokihiro Katsui
    Nov. 2024, 日本船舶海洋工学会講演会論文集, (39) (39), 791 - 796, Japanese, Domestic magazine
    Scientific journal

  • Tomoki Wakabayashi, Tokihiro Katsui
    Abstract Due to the recent high level of environmental regulations, there has been increasing of the attention to Energy Saving technics. One of the developing energy saving technics is the Hybrid Contra-Rotating Propeller (HCRP) propulsion system. To date HCRP propulsion system has been applied to limited numbers of ships which has special order like domestic liners in Japan [1][2]. However, HCRP is promising system to be built in major ships like bulk carriers, tankers or container ship which are operated around the world in the future because of its high propulsion efficiency. One practical subject of HCRP is a power estimation method for this complex propulsion system. In these decades, several research projects treated HCRP. TRIPOD project [3][4] treated wide range of topics, which included tank test method, numerical analysis and concept validation adopting HCRP to an existing cargo ship. The mainstream of a power estimation method for HCRP is the way how a total force of two propeller acting as a CRP are treated as pseudo one propeller [5][6]. The feature of HCRP is that two propellers can act independently. It means there exists infinity numbers of rotational speed rate of two propellers and a propulsion performance and a maneuvering performance depends on it [5]. If we use a propeller open water characteristics of a CRP as pseudo one propeller, we can estimate only very limited conditions which are tested in a towing tank. This paper shows the newly developed powering method which use characteristics of individual two propellers and a mutual interaction of propellers acting as a CRP. This method can estimate every condition of revolution rate which made with a feature of HCRP propulsion system. The scope of this research is constructing a tank test method and a powering method and reviewing them with surveying of an actual ship performance.
    American Society of Mechanical Engineers, Jun. 2024, Proceedings of ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering, English, International magazine
    [Refereed]
    International conference proceedings

  • Tatsuya Kaneko, Tomoya Inoue, Ryota Wada, Tokihiro Katsui, Hiroyoshi Suzuki
    Abstract Understanding drill-string dynamics is essential to improving offshore drilling efficiency and preventing accidents. Previous studies have mainly focused on self-excited oscillations due to stick-slip and bit-bounce. However, in deepwater drilling, large weight-on-bit fluctuations due to ship heaving are a major concern that can affect the dynamics in the torsional direction. This paper reports analytical and numerical investigations on the torsional vibration of a drill string under weight-on-bit fluctuation. First, the analytical solution of a single-mass model showed that forced oscillations are caused by WOB fluctuations, which have not been examined extensively in previous studies. In addition, for the same amplitude of WOB variation, vibration at the heave frequency has a greater effect on torsional vibration than at the axial self-excited frequency. Furthermore, large WOB fluctuations increase the risk of stick-slip and reverse rotation of the drill bit. Second, numerical experiments with the multi-mass model yielded results similar to those of the analytical study. These results show the importance of capturing torsional vibrations caused by fluctuations in the WOB and reducing WOB fluctuations.
    American Society of Mechanical Engineers, Jun. 2024, Proceedings of ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering, English, International magazine
    [Refereed]
    International conference proceedings

  • Satoshi Matsuda, Tokihiro Katsui
    The k-omega SST turbulence model is extensively employed in Reynolds-averaged Navier–Stokes (RANS)-based Computational Fluid Dynamics (CFD) calculations. However, the accuracy of the estimation of viscous resistance and companion flow distribution for full-sized vessels is not sufficient. This study conducted a computational analysis of the flow around the Ryuko-maru at model-scale and full-scale Reynolds numbers utilizing the Reynolds stress turbulence model (RSM). The obtained Reynolds stress distribution from the model-scale computation was compared against experimental measurements to assess the capability of the RSM. Furthermore, full-scale computations were performed, incorporating the influence of hull surface roughness, with the resulting wake distributions juxtaposed with the actual ship measurements. The full-scale calculation employed the sand-grain roughness function, and an optimal roughness length scale was determined by aligning the computed wake distribution with Ryuko-maru’s measured data. The results of this study will allow for the direct performance estimation of full-scale ships and contribute to the design technology of performance.
    Last, MDPI AG, May 2024, Journal of Marine Science and Engineering, 12(5) (5), 783 - 783, English, International magazine
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • The Roughness Length Scale for Coating Rough Surface
    Tokihiro Katsui, Kouki Kawane, Ryo Nishioka, Shun Kuwahara, HIrohisa Mieno
    Lead, May 2024, 日本船舶海洋工学会講演会論文集, (38) (38), 817 - 820, Japanese, Domestic magazine
    Scientific journal

  • Assessment of Roughness Models in RaNS Solver NAGISA with 2D Rotating Cylindrical Annuals
    Ryo Nishioka, Nobuaki Sakamoto, Kunihide Ohashi, Hiroshi Kobayashi, Tokihiro Katsui, Kouki Kawane, Shun Kuwahara, Hirohisa Mieno
    Corresponding, May 2024, 日本船舶海洋工学会講演会論文集, (38) (38), 807 - 815, Japanese, Domestic magazine
    Scientific journal

  • Calculation of Roughness Allowance with OpenFOAM at Ship Scale Reynolds Number
    Shun Kuwahara, Ryo Nishioka, Tokihiro Katsui
    Corresponding, May 2024, 日本船舶海洋工学会講演会論文集, (38) (38), 785 - 798, Japanese, Domestic magazine
    Scientific journal

  • Analysis of Hydrodynamic Force Acting on Lateral Motion Ships by Means of Mathematical Hull Forms; 3rd Report: Dependencies of Shallow Water Effects to the Hull Form Fineness
    Takuro Adachi, Shigeru Nishio, Kenichi Takamatsu, Tokihiro Katsui
    Nov. 2023, 日本船舶海洋工学会講演会論文集, (37) (37), 411 - 414, Japanese, Domestic magazine
    Scientific journal

  • Research Activities on Drill Pipe Dynamics
    Tomoya Inoue, Tatsuya Kaneko, Hiroyoshi Suzuki, Chang-Kyu Rheem, Ryota Wada, Tokihiro Katsui
    Nov. 2023, 日本船舶海洋工学会講演会論文集, (37) (37), 171 - 174, Japanese, Domestic magazine
    Scientific journal

  • Tatsuya Kaneko, Tomoya Inoue, Ryota Wada, Tokihiro Katsui, Hiroyoshi Suzuki
    Abstract Several studies have been conducted on the stick-slip type of torsional vibration, which reduces drilling efficiency and sometimes damages drill bits and pipes, using numerical experiments, small-scale model experiments, or field data on the land rig. However, an analytical investigation into stick-slip conditions or a field data investigation of deepwater drilling has not been sufficiently studied. This study derives the conditions for stick-slip occurrence through analytical, numerical, and field data investigations and discusses a method to reduce stick-slip vibration. First, we derive a simple expression for stick-slip using an analytical solution of a single mass-spring-damper model. Additionally, we numerically experiment using a multi-mass model to consider the mass distribution that cannot be considered in the analytical solution. Furthermore, we analyze the field data from deepwater drilling and experiment with a numerical model to examine the actual phenomena. As a result, the analytical and numerical investigations have shown that stick-slip can be prevented by appropriately adjusting the rotational speed and the weight on bit. However, the field data investigation showed that the forced torsional vibration due to the vibration of the weight on bit was predominant in deepwater drilling. In this case, suppressing the amount of fluctuation of weight on bit is crucial to reduce the torsional vibration.
    American Society of Mechanical Engineers, Jun. 2023, Proceedings of ASME 42nd International Conference on Ocean, Offshore and Arctic Engineering, English, International magazine
    [Refereed]
    International conference proceedings

  • The measurement of roughness function for painted rough surface based on rotating cylinder test
    Koki Takashima, Tokihiro Katsui, Kouki Kawane, Ryo Nishioka, Hirohisa Mieno
    Corresponding, May 2023, 日本船舶海洋工学会講演会論文集, (36) (36), 383 - 388, Japanese, Domestic magazine
    Scientific journal

  • Analytical and Numerical Investigation of the Contributing Factors of Drill Pipe Stick-Slip
    Tatsuya Kaneko, Tomoya Inoue, Ryota Wada, Tokihiro Katsui, Hiroyoshi Suzuki
    Nov. 2022, 日本船舶海洋工学会講演会論文集, (35) (35), 741 - 744, Japanese, Domestic magazine
    Scientific journal

  • Hiroyoshi Suzuki, Tomoya Inoue, Tokihiro Katsui, Ryota Wada, Keita Tsuchiya, Yusuke Notani, Keita Ishida, Taito Koga
    International Society of Offshore and Polar Engineers, Sep. 2022, International Journal of Offshore and Polar Engineering, 32(3) (3), 285 - 295, English, International magazine
    [Refereed]
    Scientific journal

  • Satoshi Matsuda, Tokihiro Katsui
    The Reynolds-averaged Navier–Stokes (RANS)-based computational fluid dynamics (CFD) calculation using a two-equation turbulence model, such as the k–omega shear-stress transport (SST) model, is a mainstream method with sufficient accuracy for the estimation of integral hydrodynamic forces and moment at both the model-scale and full scale. This paper confirmed that the Reynolds stress model (RSM) has sufficient estimation accuracy of viscous resistance and wake distribution at the hull design stage. Herein, the ability of RSMs to estimate the viscous resistance and wake distribution of a JBC ship is evaluated. Specifically, the verification and validation (V&V) method is employed to indicate the numerical and model uncertainties of each turbulence model used to estimate the viscous resistance. The RSMs showed higher numerical uncertainty than the k–omega SST. However, the uncertainty of the experimental measurements is generally smaller than the numerical uncertainty. Moreover, the linear pressure–strain (LPS) and the linear pressure–strain two-layer (LPST) models show less comparison error of the viscous resistance than the k–omega SST. Furthermore, the LPST and k–omega SST models are applied to twenty ships with various full and fine hull forms to calculate the viscous resistance and compare it with the experimental results. The viscous resistance of the LPST model showed a small difference when employed in experimental fluid dynamics (EFD) and CFD calculations. Using the LPST model, the viscous resistance can be estimated with high accuracy in our setting. For industrial use, this study could provide an important insight into the designing of various types of vessels.
    MDPI AG, Jun. 2022, Journal of Marine Science and Engineering, 10(6) (6), 777 - 777, English, International magazine
    [Refereed]
    Scientific journal

  • Experimental and Numerical Studies on Behavior of Rotating Model Drill Pipe in Uniform Flow
    Hiroyoshi Suzuki, Tomoya Inoue, Tokihiro Katsui, Ryota Wada, Keita Tsuchiya, Yusuke Notani, Keita Ishida, Taito Koga
    Jun. 2022, Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference, 1885 - 1893, English, International magazine
    [Refereed]
    International conference proceedings

  • Study on Full-scale Ship CFD Simulations Calculated by RSM
    Satoshi Matsuda, Tokihiro Katsui, Koyu Kimura
    May 2022, 日本船舶海洋工学会講演会論文集, (34) (34), 291 - 294, Japanese, Domestic magazine
    Scientific journal

  • The Direct Measurement of Roughness Function for Painted Rough Surfaces Using Double Rotating Cylinder
    Tokihiro Katsui, Hideaki Yoshioka, Koki Takashima, Kouki Kawane, Hirohisa Mieno, Shigeru Nishio
    Lead, May 2022, 日本船舶海洋工学会講演会論文集, (34) (34), 287 - 290, Japanese, Domestic magazine
    Scientific journal

  • Analysis of Hydrodynamic Force Acting on Lateral Motion Ships by Means of Mathematical Hull Forms; 2nd Report: Dependencies of Shallow Water Effects to the Aspect Ratio of Hulls
    Shogo Kitaji, Shigeru Nishio, Kenichi Takamatsu, Tokihiro Katsui
    May 2022, 日本船舶海洋工学会講演会論文集, (34) (34), 355 - 359, Japanese, Domestic magazine
    Scientific journal

  • Analysis of Hydrodynamic Force Acting on Lateral Motion Ships by Means of Mathematical Hull Forms
    Keitaro Kohara, Shigeru Nishio, Kenichi Takamatsu, Tokihiro Katsui
    Nov. 2021, 日本船舶海洋工学会講演会論文集, (33) (33), 381 - 384, Japanese, Domestic magazine
    Scientific journal

  • Machine Learning Approach with Physical Model-Based Simulation Data to Predict the Lithologies of Drilling Layers
    Tomoya Inoue, Yujin Nakagawa, Tokihiro Katsui, Ryota Wada, Hakan Bilen, Hiroyoshi Suzuki
    Nov. 2021, 日本船舶海洋工学会講演会論文集, (33) (33), 157 - 160, Japanese, Domestic magazine, Co-authored internationally
    Scientific journal

  • Numerical Investigation of Stick-Slip Phenomenon in Ocean Drilling
    Daisuke Sogawa, Tokihiro Katsui, Tomoya Inoue, Ryota Wada, Hiroyoshi Suzuki
    Corresponding, May 2021, 日本船舶海洋工学会講演会論文集, (32) (32), 593 - 596, Japanese, Domestic magazine
    Scientific journal

  • A Study on Tsunami Mitigation Effect of Embankment
    Efu Nishimura, Hiroya Murata, Tokihiro Katsui
    Corresponding, May 2021, 日本船舶海洋工学会講演会論文集, (32) (32), 233 - 236, Japanese, Domestic magazine
    Scientific journal

  • Estimation of Roughness Resistance for Painted Rough Surface
    Koki Takashima, Tokihiro Katsui, Hirohisa Mieno
    Corresponding, May 2021, 日本船舶海洋工学会講演会論文集, (32) (32), 245 - 248, Japanese, Domestic magazine
    Scientific journal

  • Advanced Quality Control of Uncertainties for the Measurement of Unsteady Hydrodynamic Forces; Study on Non-Uniform Uncertainties of Regression Analysis and Higher-Order Propagation
    Kosuke Kubo, Shigeru Nishio, Kenichi Takamaatsu, Tokihiro Katsui
    Nov. 2020, 日本船舶海洋工学会講演会論文集, (31) (31), 69 - 73, Domestic magazine

  • Behavior of Hydrodynamic Force Acting on a Berthing Ship in Extreme Shallow Water (2nd report: Analysis of Response Factors and the Validation by means of Measurement)
    Saki Shintani, Shigeru Nishio, Tokihiro Katsui
    May 2020, 日本船舶海洋工学会講演会論文集, (30) (30), 589 - 592, Japanese, Domestic magazine
    Scientific journal

  • Hirohisa Mieno, Tokihiro Katsui
    Springer Science and Business Media LLC, Mar. 2020, Journal of Marine Science and Technology, 26(1) (1), 1 - 15, English, International magazine
    [Refereed]
    Scientific journal

  • Analysis of the Correlation between Hull Form Factor and Behavior Change of Hydrodynamic Force Acting on Ships at Lateral Motion in Extreme Shallow Water
    Shigeru Nishio, Yuta Konishi, Utako Tanizawa, Tokihiro Katsui
    Nov. 2019, 日本船舶海洋工学会講演会論文集, (29) (29), 473 - 476, Japanese, Domestic magazine
    Scientific journal

  • Tomoya Inoue, Hiroyoshi Suzuki, Tokihiro Katsui, Keita Tsuchiya, Yusuke Notani
    Abstract During riserless drilling operations conducted in some scientific drillings and the initial stages of all oil and gas drilling operations, drill pipe motions such as vortex induced vibration, whirl motion, and motion due to the Magnus effect are generated. The last motion represents an interesting and important phenomenon that generates a lift force in addition to a drag force due to the ocean current and the rotation of the drill pipe. Accordingly, this study focuses on the drill pipe motions owing to the Magnus effect. An analytical model of a drill pipe was established by applying an absolute nodal coordinate formulation (ANCF) that can capture the behavior of a relatively flexible and long pipe, such as a drill pipe. The lifting and drag forces are calculated using computational fluid dynamics (CFD), and the lift and drag coefficients are calculated for several different drill pipe rotational velocities and ocean current velocities. A series of model experiments were conducted in a towing tank, with changing water flow velocities and rotational speed of the drill pipe model to observe the corresponding changes in the Magnus effect and to measure the resulting drill pipe motions. Additionally, the resulting drag and lift forces were measured. It was observed from the experiments that the motions in the cross-flow direction increased as the rotational speed of the drill pipe model increased, and that the lifting force increased as the rotational speed increased. The drill pipe motions were then simulated using a previously established analytical model and the results of the CFD simulations. The results of the simulations were evaluated against the results of the experiments, and reasons for observed discrepancies are discussed.
    American Society of Mechanical Engineers, Jun. 2019, Proceedings of ASME 38th International Conference on Ocean, Offshore and Arctic Engineering, English, International magazine
    [Refereed]
    International conference proceedings

  • Tokihiro Katsui, Tomoya Inoue, Daisuke Sogawa, Yusuke Notani
    Abstract The Stick-Slip is one of troublesome problems which happens in scientific drilling. In order to clarify the mechanism of Stick-Slip phenomenon, it is necessary to develop a reliable numerical model [1]-[4] to estimate drill bit motion for various drilling conditions. We have investigated on an NDDE (Neutral Delay Differential Equation) [5] to solve Stick-Slip of drill pipe [6]-[8]. In order to solve this NDDE, it is necessary to determine the frictional torque acting on the drill bit. In the previous study, we have employed the Balanov’s [4] frictional torque model which is the function of drill bit rotation with four unknown model parameters. This numerical model calculates the Stick-Slip phenomena of the drill pipe model in the laboratory experiments correctly under the appropriate four model parameter settings. On the other hand, it is quite difficult to calculate the actual drill pipe Stick-Slip [9], because the calculated results change drastically depending on the four unknown parameter settings. In the present study, the frictional torque acting on the drill bit is defined as a periodic function and solved the NDDE to calculate the stick-slip of the actual drill pipe. The average, variation and period of the frictional torque on the drill bit were set under the consideration of measured top drive torques. The calculated numerical solutions of the drill bit motion and the top drive torque agreed qualitatively with the measured ones.
    Lead, American Society of Mechanical Engineers, Jun. 2019, Proceedings ASME 38th International Conference on Ocean, Offshore and Arctic Engineering, English, International magazine
    [Refereed]
    International conference proceedings

  • Hirohisa Mieno, Tokihiro Katsui
    Springer Science and Business Media LLC, Jun. 2019, Journal of Marine Science and Technology, 25(2) (2), 498 - 509, English, International magazine
    [Refereed]
    Scientific journal

  • Experimental and Numerical Study on Underwater Behavior of Rotating Drill Pipe
    Hiroyoshi Suzuki, Keita Tsuchiya, Tomoya Inoue, Tokihiro Katsui, Hidetaka Senga, Yuhi Nagaishi, Yusuke Notani
    Nov. 2018, 日本船舶海洋工学会講演会論文集, (27) (27), 357 - 364, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro Katsui, Hisao Tanaka
    The present study shows a method to evaluate the performance of the paints to reduce the additional frictional resistance in full scale ship Reynolds number. Simultaneous non-linear ordinary differential equations are developed to calculate the hydrodynamic frictional resistance of flat plate based on the momentum equation and Coles’ wall wake law which is the similarity law of the velocity distribution in the turbulent boundary layer. Roughness influence of painted surface is taken into account by adding the roughness function to Coles’ wall wake law. The expression of the roughness function should be determined based on the experimental results of the additional frictional resistance for various kinds of paints. The obtained roughness function depends on the roughness Reynolds number, and it also depends on both the roughness wave height and wave length fraction to its height which are obtained FFT analysis for measured paint surface profiles. The calculated local frictional stress coefficients on the painted surfaces well agreed with the measured ones. The total frictional resistance coefficients of painted surface in the actual ship scale Reynolds number can be evaluated considering influence of surface roughness.
    Lead, American Society of Mechanical Engineers, Jun. 2018, Proceedings of ASME 37th International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • Raditya Hendra Pratama, Akira Sou, Tokihiro Katsui, Shigeru Nishio
    Begell House, Dec. 2017, Atomization and Sprays, 27(3) (3), 189 - 205, English
    [Refereed]
    Scientific journal

  • ドリルパイプ模型のStick-Slip現象の計測と数値解析
    福田聡太, 永石雄飛, 勝井辰博, 井上朝哉, 鈴木博善
    ドリルパイプの非定常Stick-Slip現象の模型試験による計測と数値解析を行ったもの。これまでになかった非定常の数値解析法を示し，模型試験との比較を行ったもの。ドリルビットに作用する摩擦モデルのモデルパラメタに時間依存項を組み込むことにより，定量的に非定常Stick-Slipを予測できる数値モデルを示した。
    Corresponding, Nov. 2017, 日本船舶海洋工学会講演会論文集, (25) (25), 665 - 669, Japanese, Domestic magazine
    Scientific journal

  • 新しい粗度関数を用いたペイント粗面に対する摩擦抵抗推定の試み
    勝井辰博, 鎌田京介, 田中寿夫
    ペイント粗面に対する平板摩擦抵抗係数の算定法を示したもの。基礎とする方程式は運動量積分式と摩擦速度に基づく平板乱流境界層内速度分布の相似則であるColes' Lawであるが，粗面による境界層内速度分布の減速量を表す粗度関数を各種ペイント粗面の粗度抵抗増加量から逆算して算定したうえで，平板摩擦抵抗を算定した。
    Lead, Nov. 2017, 日本船舶海洋工学会講演会論文集, (25) (25), 757 - 760, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro Katsui, Tomoya Inoue, Kenta Izutani, Yuhi Nagaishi, Chang-Kyu Rheem, Miki Y. Matsuo
    Lead, Jun. 2017, Proceedings of ASME 36th International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • 調和解析器について
    鈴木敏夫, 内藤林, 池渕哲郎, 坪郷尚, 勝井 辰博
    機械的な仕組みによってフーリエ解析が可能な調和解析器の作動原理とその操作方法,計算精度について実機を用いて検証したもの．技術機器遺産としての評価が高い調和解析器についてその価値が検証されている．
    May 2017, 日本船舶海洋工学会講演論文集, (24) (24), 89 - 90, Japanese, Domestic magazine
    Scientific journal

  • Kenichi Takamatsu, Shigeru Nishio, Tokihiro Katsui
    Japan Society of Naval Architects and Ocean Engineers, Dec. 2016, Journal of the Japan Society of Naval Architects and Ocean Engineers, (24) (24), 1 - 12, Japanese
    [Refereed]
    Scientific journal

  • Tokihiro Katsui, Ryuichi Sakamoto, Masanari Akashi, Tomoya Inoue
    Lead, Japan Society of Naval Architects and Ocean Engineers, Dec. 2016, Journal of the Japan Society of Naval Architects and Ocean Engineers, (24) (24), 275 - 281, Japanese
    [Refereed]
    Scientific journal

  • 離着岸船舶に作用する操縦流体力の極浅水域における特性変化
    相澤流, 西尾茂, 勝井 辰博
    極浅水域を横移動するときの船舶に作用する過大な流体力について，数値流体力学的手法をもとに解析したもの．離着岸時は船体の近傍に岸壁が存在するため，浅水影響と岸壁影響が複合して，船体に作用する流体力が顕著に大きくなることが確かめられた．
    日本船舶海洋工学会, Nov. 2016, 日本船舶海洋工学会講演論文集, (23) (23), 141 - 144, Japanese, Domestic magazine
    Scientific journal

  • 津波数値シミュレーションにおける簡便な水陸境界更新法
    河内暁, 田中悠貴, 勝井 辰博
    有限体積法に基づいた津波数値シミュレーション法の新しい水陸境界更新法を構築したもの．水陸境界の更新が計算安定性に最も大きな影響を与えることから，流量保存のみを考慮した簡便な方法を示し，ロバストな計算が実施でき，かつ妥当な精度で孤立波の遡上を計算できることを示した．
    Corresponding, Nov. 2016, 日本船舶海洋工学会講演論文集, (23) (23), 89 - 90, Japanese, Domestic magazine
    Scientific journal

  • 極浅水域における横移動船舶に作用する流体力の特性変化 -第3報：水路幅との複合要因分析-
    糸田龍一郎, 西尾茂, 勝井 辰博
    極浅水域を横移動するときの船舶に作用する過大な流体力について，数値流体力学的手法をもとに解析したもの．本報では，極浅水に加えて水路幅が制限された場合の流体力の変化を流場の変化に着目して論じた．
    日本船舶海洋工学会, Nov. 2016, 日本船舶海洋工学会講演論文集, (23) (23), 145 - 148, Japanese, Domestic magazine
    Scientific journal

  • Tomoya Inoue, Tokihiro Katsui, Junya Ishiwata, Miki Y. Matsuo, C. K. Rheem
    Jun. 2016, Proceedings of ASME 35th International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • 実計測データによるドリルパイプ下端のドリルビット挙動およびStick-Slip発生 に関する考察
    井上朝哉, 勝井辰博, 石渡準也
    ドリルパイプのSticl-Slip現象の数値シミュレーション法を用いて，実海域のドリルパイプのStick-Slipの解析を行い，実海域ドリリング時の計測データと比較検証を行ったもの．実測データは計測間隔が長いため，時系列の定量的な比較は難しいが，統計的には概ね両者は一致することが分かった．
    日本船舶海洋工学会, May 2016, 日本船舶海洋工学会講演会論文集, (22) (22), 571 - 573, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro KATSUI, Shigeru NISHIO, Runa OZAKI, Shino NAKAMURA
    Lead, Japan Society of Naval Architects and Ocean Engineers, Dec. 2015, Journal of the Japan Society of Naval Architects and Ocean Engineers, (22) (22), 67 - 73, Japanese
    [Refereed]
    Scientific journal

  • 海底摩擦の変動を考慮したドリルパイプのStick-Slipの数値解析
    泉谷健太, 勝井 辰博, 井上朝哉, 山本美希, 林昌奎
    リルパイプのSticl-Slip現象の数値シミュレーション法に関する研究．計測されるStick-Slipのスリップ量や周期が変化するのは，海底摩擦の変動に起因するとの考えから，海底摩擦トルクに時間変動を組み込んだモデルを提案し数値解析を実施したところ，実験結果をよく説明できる結果を得た．
    Corresponding, 日本船舶海洋工学会, Nov. 2015, 日本船舶海洋工学会講演会論文集, (21) (21), 147 - 150, Japanese, Domestic magazine
    Scientific journal

  • Preliminary Study of Whirl Motions of Drill Pipe
    Tomoya Inoue, Miki Y. Matsuo, Chang-Kyu Rheem, Hide Sakaguchi, Tokihiro Katsui
    Sep. 2015, Proceedings of 7th International Conference on Hydroelasticity on Marine Technology, 1 - 6, English
    [Refereed]
    International conference proceedings

  • Consideration of Hydrodynamic Effect on Drill Pipe Stick-Slip
    Tomoya Inoue, Tokihiro Katsui, Miki Y. Matsuo, Hide Sakaguchi, Chang-Kyu Rheem
    Sep. 2015, Proceedings of 7th International Conference on Hydroelasticity on Marine Technology, 7 - 13, English
    [Refereed]
    International conference proceedings

  • ドリルパイプのStick-Slip 現象に関する数値解析
    泉谷健太, 勝井 辰博, 井上朝哉, 山本美希, 林昌奎
    ドリルパイプのSticl-Slip現象を解析するための数値解析手法を示したもの．円管の捩じり振動方程式を基礎とする中立型遅延微分方程式の数値解を示し，ドリルパイプ模型のStick-Slipの計測結果とよく一致することを示した．
    Corresponding, Aug. 2015, 第25回海洋工学シンポジウム講演論文集, 431 - 436, Japanese, Domestic magazine
    Symposium

  • Tomoya Inoue, Tokihiro Katsui, Kohtaro Ujiie, Junya Ishiwata
    Jun. 2015, Proceedings of ASME 34th International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • Tokihiro Katsui, Yoshitomo Mogi, Tomoya Inoue, Chang-Kyu Rheem, Miki Y. Matsuo
    Lead, Jun. 2015, Proceedings of ASME 34th International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • Tokihiro Katsui, Maiko Nishino, Tomoya Inoue
    Seafloor exploration and seabed resources development are important missions for solving international energy issues. The crawler driven ROV which is capable to do heavy works is considered as one of the probable systems for those missions and some have been developed already. It is well known that the movability of actual ROVs on the sea floor is worse compared with the terrestrial crawlers. Therefore it is important to make clear what conditions have to be satisfied for the stable running of a ROV on the sea bottom. The experimental investigation on the crawler based ROV's movability suggests that light weight ROVs are easy to run in bow up condition and sometimes turn over. The authors have shown the condition for the normal running of the ROV which moves on the horizontal and inclined flat water bottom by means of a simple dynamic model. In this paper, a method to estimate the ROVs' ability to climb up the bumps is shown and it is validated by model experiments. The ROV model has three sets of crawlers;the centered main crawlers are set horizontally, the fore and rear crawlers are movable just like the flipper of the pinball to climb up the bumps. The requirements for the design parameters of ROV to climb up the bumps such as crawler length, weight and displacement of ROV, location of gravity and buoyancy center, derived from present method agreed with the experimental results qualitatively.
    Lead, Japan Society of Naval Architects and Ocean Engineers, Dec. 2014, Journal of the Japan Society of Naval Architects and Ocean Engineers, (20) (20), 165 - 172, Japanese
    [Refereed]
    Scientific journal

  • ドリルパイプのStick-Slip 現象に関する模型実験
    茂木 克興, 勝井 辰博, 井上 朝哉, 泉谷 健太
    ドリルパイプのSticl-Slip現象の模型実験を行ったもの．適当な剛性を有するテフロン管を用いてドリルパイプ模型を作成し，ジャイロセンサーによって，ドリルビット部とトップの回転速度を計測するとともにトップドライブトルクを同時に計測した．典型的なStick-Slipが計測され，トップドライブトルクはドリルビットの運動に大きく影響されることが分かった．
    Corresponding, 日本船舶海洋工学会, Nov. 2014, 日本船舶海洋工学会講演会論文集, (19) (19), 529 - 532, Japanese, Domestic magazine
    Scientific journal

  • Tomoya Inoue, Tokihiro Katsui, Chang-Kyu Rheem, Zengo Yoshida, Miki Y. Matsuo
    Jun. 2014, Proceedings of ASME 33rd International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • Tokihiro Katsui, Tomoya Inoue, Masanori Kyo, Hiroyoshi Suzuki
    Lead, Jun. 2014, Proceedings of ASME 33th International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • 船上掘削データからみた東北沖地震震源域掘削
    井上 朝哉, 氏家 恒太郎, 勝井 辰博, 片岡 翔, 石渡 隼也
    JAMSTECが実施した東北沖地震震源域掘削時のドリルパイプの船上掘削データから，海底下の地質学的特性の把握を試みたもの．船上で計測されるデータはドリルパイプのトップドライブトルクであり，その時間平均値や時間変動が，海底下の地質の特性と相関があることが分かった．
    May 2014, 日本船舶海洋工学会講演会論文集, (18) (18), 63 - 64, Japanese, Domestic magazine
    Scientific journal

  • 極浅水域における横移動船舶に作用する流体力の特性変化 第2 報：船型要素が及ぼす影響について
    尾崎 瑠菜, 勝井 辰博, 西尾 茂, 中村 梓乃
    極浅水域を横移動する船舶に作用する流体力について，船型が与える影響を論じたもの．肥大なタンカー船型と痩せ形のコンテナ船型を用いた流場解析を実施し，痩せ形のコンテナ船型のほうが，船底と海底のクリアランスが小さくなったときに船底から船首尾を回り込む流れに変化しやすいことが分かった．
    日本船舶海洋工学会, May 2014, 日本船舶海洋工学会講演会論文集, (18) (18), 351 - 354, Japanese, Domestic magazine
    Scientific journal

  • 極浅水域における横移動船舶に作用する流体力の特性変化
    中村 梓乃, 西尾 茂, 勝井 辰博, 尾崎 瑠菜
    極浅水域を横移動する船舶に作用する流体力を計算流体力学の手法を用いて論じたもの．船底と海底のクリアランスが小さくなると船底を回り込む流れから，船首尾を回り込む流れへと変化していき，その結果背面側により大きな渦が生成されることが過大な横力を生みだすことを見出した．
    日本船舶海洋工学会, Nov. 2013, 日本船舶海洋工学会講演会論文集, (17) (17), 311 - 314, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro Katsui, Tomoya Inoue, Masanari Akashi
    Lead, Jun. 2013, Proceedings of ASME 32nd International Conference on Ocean, Offshore and Arctic Engineering, English
    [Refereed]
    International conference proceedings

  • 実海域掘削データのドリルパイプ疲労累積推算への活用について
    井上 朝哉, 勝井 辰博
    ドリルパイプは長時間回転にさらされるため，疲労強度の評価が重要である．本研究では，FEM解析に基づく応力評価をもとにドリルパイプの疲労累積の評価を行うとともに，安全に使用できる期間推定する手法を示した．
    日本船舶海洋工学会, May 2013, 日本船舶海洋工学会講演会論文集, (16) (16), 507 - 510, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro Katsui, Satoshi Kajikawa, Tomoya Inoue
    Lead, Jun. 2012, Proceedings of ASME 31st International Conference on Ocean, Offshore and Arctic Engineering, 23 - 30, English
    [Refereed]
    International conference proceedings

  • 有限体積法に基づく津波遡上シミュレーション法の開発
    勝井 辰博, 塚本 尭芳, 山下 大輝
    有限体積法を基礎とする津波の数値シミュレーション法を開発したもの．検査体積法に基づく定式化を行い，水深方向への流速変化がない，鉛直方向の流速がない，の2つの仮定は，いわゆる浅水近似と等価であることを示した．孤立波の遡上問題に本手法を適用し，妥当な精度で遡上が解析できることを示した．
    Lead, 日本船舶海洋工学会, May 2012, 日本船舶海洋工学会講演会論文集, (14) (14), 73 - 76, Japanese, Domestic magazine
    Scientific journal

  • Hard rock coring at the steep terrain seafloor with the flipper crawler ROV
    Tomoya Inoue, Hiroyuki Osawa, Ken Takagi, Akira Asada, Masashi Mochizuki, Tokihiro Katsui, Shingo Tsukui
    2012, Underwater Intervention Conference 2012, UI 2012, 866 - 870, English
    International conference proceedings

  • 平板摩擦抵抗に与える表面粗度影響
    勝井 辰博, 泉 卓志, 上野 諭
    運動量積分式とCole's Lawに基づいた平板摩擦抵抗算定式にWhiteの粗度関数を組み込んで，粗面平板の摩擦抵抗を算定する手法を示した．この手法は2つの非線形連立微分方程式の初期値問題を解くことに帰着されており，得られた数値解析結果は船舶の粗度抵抗増加の経験則におおむね沿ったものであることが分かった．
    Lead, 日本船舶海洋工学会, Nov. 2011, 日本船舶海洋工学会講演会論文集, (13) (13), 405 - 408, Japanese, Domestic magazine
    Scientific journal

  • ケーブル張力を考慮したクローラ型ROV の可動範囲解析
    明石 雅成, 勝井 辰博, 井上 朝哉
    クローラー型ROVがアンビリカルケーブルの高速下にあるとき，どの程度の範囲で走行が可能であるかを推定する手法を開発したもの．弾性ケーブルの張力を簡便に計算する手法が示され，短時間で可動範囲を推定できることが特徴である．得られた結果は，模型試験結果とよく一致した．
    Corresponding, 日本船舶海洋工学会, Nov. 2011, 日本船舶海洋工学会講演会論文集, (13) (13), 373 - 376, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro Katsui, Masanari Akashi, Satoshi Kajikawa, Tomoya Inoue
    Lead, Jun. 2011, Proceedings ASME 30th International Conference on Ocean, Offshore and Arctic Engineering, 105 - 111, English
    [Refereed]
    International conference proceedings

  • PIV計測における誤差発生の周波数特性と精度評価法に関する研究
    川勝 麻由, 西尾 茂, 勝井 辰博
    PIV計測の際の誤差発生の要因を調査し，その周波数特性を明らかにしたもの．これにより，PIV計測の精度評価ができることを示した．
    可視化情報学会, 2011, 可視化情報学会誌, (31(Suppl.1)) (31(Suppl.1)), 3 - 6, Japanese, Domestic magazine
    Scientific journal

  • Moving performance of a flipper type crawler driven ROV
    Tokihiro Katsui, Satoshi Kajikawa, Tomoya Inoue
    Lead, Jul. 2010, Proceedings of the 5th Asia-Pacific Workshop on Marine Hydrodynamics (APHydro2010), 339 - 344, English, International magazine
    International conference proceedings

  • Tokihiro Katsui, Hisataka Murakami, Satoshi Kajikawa, Tomoya Inoue
    Lead, Jun. 2010, Proceedings ASME 29th International Conference on Ocean, Offshore and Arctic Engineering, 41 - 47, English
    [Refereed]
    International conference proceedings

  • Tomoya Inoue, Tokihiro Katsui, Hisataka Murakami, Ken Takagi
    Marine Technology Society, Dec. 2009, Marine Technology Society Journal, 43(5) (5), 97 - 104, English
    [Refereed]
    Scientific journal

  • Toru Katayama, Masanori Kotaki, Tokihiro Katsui, Akihiko Matsuda
    Japan Society of Naval Architects and Ocean Engineers, Jun. 2009, Journal of the Japan Society of Naval Architects and Ocean Engineers, (9) (9), 115 - 125, Japanese
    [Refereed]
    Scientific journal

  • Tomoya Inoue, Tokihiro Katsui, Hisataka Murakami, Junichiro Tahara
    Jun. 2009, Proceedings of ASME 28th International Conference on Ocean, Offshore and Arctic Engineering, 1369 - 1376, English
    [Refereed]
    International conference proceedings

  • Preliminary Research on the Thruster Assisted Crawler System for a Deep Sea ROV
    Tomoya Inoue, Tokihiro Katsui, Hisataka Murakami, Junichiro Tahara, Takashi Sinbori
    2009, Proceedings of OCEANS 2009, 683 - 687, English, International magazine
    International conference proceedings

  • Murakami Hisataka, Inoue Tomoya, Katsui Tokihiro
    クローラー型ROVは海底走行時にいわゆるウィリー状態となることがあり，安定走行の条件を把握することが重要である．本研究ではROVの重量，浮力，重心位置，浮心位置および水中走行時の抵抗とその作用点によって表わされるクローラー型ROVの水中安定走行条件を新たに示した．ROV模型を作製して水槽試験を行い，本研究で示した水中安定走行条件がおおむね正しいことを示した．
    Corresponding, The Japan Society of Naval Architects and Ocean Engineers, Nov. 2008, Conference Proceedings The Japan Society of Naval Architects and Ocean Engineers, (7K) (7K), 41 - 44, Japanese, Domestic magazine
    Scientific journal

  • Numerical Investigation on Running Attitude of Planing Craft
    Tokihiro Katsui, Toru Katayama, Kenji Mochizuki
    揚力面理論を拡張した滑走艇の船底圧力分布計算手法を用い，滑走艇の航走姿勢を推定する手法を示したもの．ポテンシャル解析に基づくこの手法では，船体に作用する抵抗は誘導抵抗のみとなるため，計算される航走時浸水面積をもとに摩擦抵抗を推定し，航走姿勢推定法に組み込んだ．これにより航走姿勢精度が向上することが分かった．
    Lead, Oct. 2008, Proceedings of the 3rd Pan Asian Association of Maritime Engineering Societies and Advanced Maritime Engineering Conference, 501 - 506, English, International magazine
    International conference proceedings

  • Toru Katayama, Tokihiro Katsui, Akihiko Matsuda
    The Japan Society of Naval Architects and Ocean Engineers, Oct. 2008, Proc. of the 3rd Pan Asian Association of Maritime Engineering Societies and Advanced Maritime Engineering Conference, 169 - 175, English, International magazine
    International conference proceedings

  • Tomoya Inoue, Tokihiro Katsui, Junichiro Tahara, Kazuaki Itoh, Hiroshi Yoshida, Shojiro Ishibashi, Ken Takagi
    Sep. 2008, Proceedings of OCEANS 2008, English, International magazine
    International conference proceedings

  • Katsui Tokihiro, Katayama Toru, Mochizuki Kenji
    滑走艇の高速化に伴って船側が水に濡れない，いわゆるチャインドライ状態で航走する滑走艇が増えつつある．著者らはこれまで，独自の滑走艇まわりの流場解析手法を開発してきたが，本研究では仮想浸水面法という手法を新たに開発し，チャインドライ状態の流場解析を可能とした．実験結果との比較によって本手法の有用性を示した．
    Lead, The Japan Society of Naval Architects and Ocean Engineers, May 2008, Conference Proceedings The Japan Society of Naval Architects and Ocean Engineers, (6) (6), 167 - 168, Japanese, Domestic magazine
    Scientific journal

  • Tokihiro Katsui
    Lead, Japan Society of Naval Architects and Ocean Engineers, Dec. 2007, Journal of the Japan Society of Naval Architects and Ocean Engineers, (6) (6), 167 - 175, Japanese
    [Refereed]
    Scientific journal

  • Katsui Tokihiro, Katayama Toru
    ポテンシャル理論に基づく滑走艇まわりの流場解析手法を用い,揚力と重量の一致条件および揚力中心と重心の一致条件から得られる連立微分方程式を解くことで，滑走艇の定常航走姿勢を求めた．対象船型として25ftクラスの実用型滑走艇船型の定常航走姿勢の計算を行い，1ｍ模型を用いて行った実験結果と比較した．
    Lead, The Japan Society of Naval Architects and Ocean Engineers, Nov. 2007, Conference Proceedings The Japan Society of Naval Architects and Ocean Engineers, (5K) (5K), 107 - 108, Japanese, Domestic magazine
    Scientific journal

  • Masakazu Arima, Wataru Sumino, Atsushi Toyoda, Tokihiro Katsui, Taketoshi Okuno
    Japan Society of Naval Architects and Ocean Engineers, Dec. 2006, Journal of the Japan Society of Naval Architects and Ocean Engineers, (4) (4), 31 - 37, Japanese
    [Refereed]
    Scientific journal

  • Tokihiro Katsui
    Lead, Japan Society of Naval Architects and Ocean Engineers, Dec. 2006, Journal of the Japan Society of Naval Architects and Ocean Engineers, (4) (4), 167 - 174, Japanese
    [Refereed]
    Scientific journal

  • Tokihiro Katsui, Takashi Tomita
    Lead, Japan Society of Naval Architects and Ocean Engineers, Dec. 2006, Journal of the Japan Society of Naval Architects and Ocean Engineers, (4) (4), 175 - 183, Japanese
    [Refereed]
    Scientific journal

  • 滑走艇の定常航走姿勢シミュレーション
    勝井辰博, 片山徹
    ポテンシャル理論に基づく滑走艇まわりの流場解析手法を用い,揚力と重量の一致条件および揚力中心と重心の一致条件から得られる連立微分方程式を解くことで，滑走艇の定常航走姿勢を求めた．デッドライズアングルが13[deg]の柱状滑走艇の定常航走姿勢を求めた．
    Lead, Nov. 2006, 日本船舶海洋工学会講演会論文集, (3) (3), 247 - 248, Japanese, Domestic magazine
    Scientific journal

  • Numerical Simulation of Wetted Surface Area and Hydrodynamic Force Acting on a Planing Ship
    Tokihiro Katsui
    Lead, Oct. 2006, Proceedings of the 2nd Pan Asian Association of Maritime Engineering Societies and Advanced Maritime Engineering, 117 - 122, English
    [Refereed]
    Scientific journal

  • Development of an Underwater Glider with Independently Controllable Main Wings
    M.Arima, A.Toyoda, K.Higuchi, T.Katsui, T.Okuno, W.Sumino
    Oct. 2006, Proceedings of TECHNO-OCEAN 2006, CD-ROM, English
    [Refereed]
    International conference proceedings

  • 主翼独立制御型水中グライダー実験機の設計と開発
    有馬正和, 豊田篤史, 住野亘, 勝井辰博, 奥野武俊
    左右の主翼をそれぞれ独立に制御できる水中グライダーのモデル機を設計・製作を行ったもの．バラストの位置と，窒素ガスの充填量を変化させることにより，潜航および浮上が可能であり，主翼を独立に制御することにより運動性能を向上させることを目指している．また，通常の水中グライダーでは難しかった浅い角度で潜航・浮上か可能である．
    May 2006, 日本船舶海洋工学会講演会論文集, (2K) (2K), 57 - 60, Japanese, Domestic magazine
    Scientific journal

  • 滑走艇の航走時浸水面形状と流体力推定シミュレーション
    勝井辰博, 甲滝昌功
    航走時浸水面形状とそこに作用する流体力を求めるための未定境界連立積分方程式の数値解法を示した．線形揚力面積分方程式と同様の特異性が浸水面の前縁境界であるスプレールートライン上に現れるため，Vortex Lattice法とMode Function法を組み合わせたハイブリッド法を提案し，精度よく積分方程式の数値解を得る手法を示した．
    Lead, May 2006, 日本船舶海洋工学会講演会論文集, (2K) (2K), 169 - 172, Japanese, Domestic magazine
    Scientific journal

  • 線図フェアリング自動化に関する基礎的研究
    勝井辰博, 樋口誉英
    船舶の形状図面（線図）の平滑化作業であるフェアリングの自動化を目標として行われたもの．本研究では曲線のポキュパイン分布に着目した曲線の非平滑指標を最小化することにより，従来法よりも高精度でフェアリングを実施することが可能であることを示した．
    Lead, May 2006, 日本船舶海洋工学会講演会論文集, (2K) (2K), 173 - 174, Japanese, Domestic magazine
    Scientific journal

  • Yusuke Tahara, Satoshi Tohyama, Tokihiro Katsui
    Feb. 2006, International Journal for Numerical Methods in Fluids, 52(5) (5), 499 - 527, English
    [Refereed]
    Scientific journal

  • Tokihiro Katsui, Koji Norisada
    The ship hull form fairing is one of costly tasks in ship hull design stage. Because the fairing task operators must be trained for a long time to acquire the skills and it is done with manual procedure even though the 3D CAD system is implemented. The present study investigates an automatic fairing method for ship hull surface which is created with the combined Coons patch. In past researches concerned with the automatic surface fairing technique, the fairing is carried out by minimizing the unfairness function of the surface with optimization method. The unfairness function is usually defined by using physical property of surface such as strain energy or by using geometrical property represented by surface curvature. However, it would appear that minimizing the strain energy of the surface sometimes changes the hull form characteristics which should be maintained. On the other hand, most of existing unfairness functions based on surface geometrical property are defined for the surface which have continuous curvature in whole area and are not applicable for the combined Coons patch surface which we use for hull surface creation, because Coons patch surface do not have continuous curvature on the boundary of the patches. Therefore the present study defines several unfairness functions with geometrical property of the surface which can be applicable to combined Coons patch surface and minimize it to obtain a faired hull surface. The present method is applied to the fairing at aft part of tanker type ship. The obtained hull surface after the fairing is smoothened compared with before the fairing and it is considered that the rough fairing is carried out successfully through the present method.
    Lead, The Japan Society of Naval Architects and Ocean Engineers, Dec. 2005, Journal of the Japan Society of Naval Architecture and Ocean Engineers, (2) (2), 161 - 168, Japanese
    [Refereed]
    Scientific journal

  • The Proposal of a New Friction Line
    Tokihiro Katsui, Yoji Himeno, Yusuke Tahara
    Lead, Mar. 2005, Proceedings of 5th Osaka Colloquium on Advanced Research on Ship Viscous Flow and Hull Form Design by EFD and CFD Approaches, 76 - 83, English
    Scientific journal

  • Development of Simulation Based Design for Ship Hydrodynamics and Fluid Engineering
    Yusukie Tahara, Tokihiro Katsui, Yoji Himeno
    Oct. 2004, Proceedings of 4th Conference for New Ship and Marine Technology, 1 - 13, English
    Scientific journal

  • Tokihiro Katsui, Naruya Komizu, Iwao Nakanishi, Yusuke Tahara, Yoji HImeno
    Adjoint variable method (AVM) is known as one of time saving sensitivity analysis method for hydrodynamic shape optimization technique based on CFD calculation and gradient based optimization algorism. But it is rare that the accuracy of the sensitivity coefficient calculated by AVM or its dependency on the computing scheme is evaluated. In this study the adjoint variable method is applied for sensitivity analysis of two dimensional viscous flow around a wing. The objective function is lift coefficient calculated from CFD analysis and design parameters are coordinates of Bezier curve's control point which form the profile of the wing. For estimating the accuracy and its dependency on the computing scheme or conditions, two kind of discretization scheme for flow computation are applied and three kind of computational grid are used. The calculated sensitivity coefficients by AVM on each condition are compared with ones which are calculated from finite differential approximation. And the influence of the convergence accuracy of adjoint equation to the calculated results of sensitivity coefficient is also evaluated.
    Lead, THE JAPAN SOCIETY OF NAVAL ARCHITECTS AND OCEAN ENGINEERS, Sep. 2004, Journal of the KANSAI Society of Naval Architects Japan, (242) (242), 9 - 15, Japanese
    [Refereed]
    Scientific journal

  • TAHARA Yusuke, KATSUI Tokihiro, KAWASAKI Masato, KODAMA Kinji, HIMENO Yoji
    This paper concerns development of large-scale high-performance (LSHP) CFD coding method for PC-Cluster Parallel Computing Environment. Main objective of the present study is enhancement of capability of Reynolds-averaged Navier-Stokes (RaNS) equation solver and its advanced applications for LSHP computing in ship hull form design. One of the finial goals is to achieve the scalable coding of RaNS equation solver in the level of 10^7 computational grids using 64 CPUs. In the present 1st report, focus of discussion is placed on setup and initial evaluation of the present coding environment. The Message Passing Interface (MPI) protocol and the Score-D job scheduling method are implemented in the present system. In the following, details of the present parallel coding environment are described. Then results of the performance evaluation are discussed based on benchmark data for high-performance parallel coding of CFD-based nonlinear programming and a domain-decomposition-based commercial RaNS equation solver.
    THE JAPAN SOCIETY OF NAVAL ARCHITECTS AND OCEAN ENGINEERS, Mar. 2004, Journal of the Kansai Society of Naval Architects, Japan, (241) (241), 47 - 58, Japanese
    [Refereed]

  • Tokihiro Katsui, Yusuke Tahara, Naruya Komizu, Yoji Himeno
    Hydrodynamic shape optimization technique based on CFD calculation is becoming popular with the development of computer. Ship hull form optimization based on CFD calculation is also carried out by many researchers. However, such kind of optimization technique is not used actively in actual ship design stage. The main reason is assumed that it requires a long time to get a solution. An optimization algorism based on gradient method usually applied in hydrodynamic shape optimization takes the large part of computation time for sensitivity analysis. The finite differential method for sensitivity analysis is simple and accurate, but takes much time. On the other hand, the adjoint variable method is known as complicated but effective method for sensitivity analysis. The present study applied the adjoint variable method for sensitivity analysis of lift coefficient acting on two dimensional foil and propose an efficient computation algorism. The calculated sensitivity coefficients by present method are compared with calculated ones by finite differential method and evaluated the availability of present method.
    Lead, THE JAPAN SOCIETY OF NAVAL ARCHITECTS AND OCEAN ENGINEERS, Sep. 2003, Journal of the Kansai Society of Naval Architects, Japan, 2003(240) (240), 47 - 53, Japanese
    [Refereed]
    Scientific journal

  • Verification of Flat-Plate Friction Coefficient at Ship-Scale Reynolds Number
    Tokihiro Katsui, Yoji Himeno, Yusuke Tahara
    Lead, Sep. 2003, Proceedings of International Symposium on Naval Architecture and Ocean Engineering, 1 - 9, English
    Scientific journal

  • Yusuke Tahara, So Sugimoto, Sinya Murayama, Tokihiro Katsui, Yoji Himeno
    This paper concerns development of a CAD/CFD/optimizer-integrated hull-form design System. The CAD, CFD, and optimizer modules are functionally independent and basically replaceable. Main objective of the present study is system development and demonstration of the capability, which justifies use of relatively simple flow and free-surface models, static sinkage and trim, and simplified design constraints. The CAD and CFD methods used in the present study are NAPA and a Rankine-source panel method, respectively. Currently, two nonlinear optimization algorithms are implemented, i.e., the successive quadratic programming (SQP) and the genetic algorithm (GA); and results are presented for the former in the present paper. For demonstration of the present approach, the bulbous bow optimization of container ship for minimum wavemaking resistance is considered. It appeared that the present CAD-based hull form modification overcomes many issues related to unrealistic solutions often seen in the related studies, which is due to the use of insufficient hull form modification methods. In conclusion, the present system has been shown very promising and warrants further investigation for more practical design constraints and conditions.
    THE JAPAN SOCIETY OF NAVAL ARCHITECTS AND OCEAN ENGINEERS, Sep. 2003, Journal of the KANSAI Society of Naval Architects Japan, 2003(240) (240), 29 - 36, English
    [Refereed]
    Scientific journal

  • A Study of Air Lubrication Method to Reduce Frictional Resistance of Ship - An experimental study using flat plate and 16m-Model -
    Akihito Hirayama, Syunji Soejima, Hideaki MIyata, Tokihiro Katsui, Yoshikazu Kasahara, Yukihiko Okamoto, Yasunori Iwasaki, Noritsugu Shimoyama
    The design of ships with low resistance has been one of the most important subjects in ship design. The method using membranous air as lubricant is one of hopeful methods to achieve this aim. Many studies of this method to reduce frictional drag have been proposed. However, concerning with the effect and air behavior at high speed, these studies leave much to be desired. For the application of air lubrication method to many kinds of vessels, the information at high speed is indispensable. To obtain the information, the experiments using 2.2m flat plate model and 16.0m ship model were carried out. As the result of the experiments, at high speed, the effect of air lubrication and the behavior of air under the device of an air lubrication method were confirmed, and it was found that the air lubrication is able to achieve significant reduction of frictional resistance of ships at high speed more than 10knots.
    The Japan Society of Naval Architects and Ocean Engineers, Jun. 2003, Journal of the West-Japan society of naval architects, (105) (105), 1 - 9, Japanese
    [Refereed]
    Scientific journal

  • Tokihiro Katsui, Yoji Himeno, Yusuke Tahara
    Lead, Mar. 2003, Journal of the Kansai Society of Naval Architects, Japan, (239) (239), 37 - 44, Japanese
    [Refereed]
    Scientific journal

  • Tokihiro Katsui, Yukihiko Okamoto, Yoshikazu Kasahara, Noritsugu Shimoyama, Yasunori Iwasaki, Shunji Soejima, Akihito Hirayama
    Experimental investigation to reduce friction drag of ship by means of air lubrication is presented. Tanker form model ship with four air injection devices on flat bottom is used. Resistance tests were carried out both in calm water and in waves. This paper also presents a method to estimate full scale ship performance with air lubrication. This method takes medel experiments under full scale ship speed into account. By this method, it is estimated that about 8% energy will be saved by air lubrication in case of VLCC>
    Lead, The Japan Society of Naval Architects and Ocean Engineers, Mar. 2003, Journal of the Kansai Society of Naval Architects, Japan, (239) (239), 45 - 53, Japanese
    [Refereed]
    Scientific journal

  • Yusuke Tahara, Tokihiro Katsui, Yoji Himeno
    計算流体力学の手法を用い実船スケールのレイノルズ数で船体周りの流場解析を行ったもの．壁関数を用いることで計算格子の数を減らし，かつ船体表面の粗度影響を壁関数に組み込み粗度による抵抗増加も評価できる手法を示した．レイノルズ数影響による伴流変化についても既存の手法との比較検証を行った．
    Japan Society of Naval Architects and Ocean Engineers, Dec. 2002, Journal of the Society of Naval Architects of Japan, (192) (192), 89 - 101, Japanese, Domestic magazine
    [Refereed]
    Scientific journal

  • Simulation of Ship Viscous Flow at Full Scale Reynolds Number
    Yusuke Tahara, Tokihiro Katsui, Yoji Himeno
    Oct. 2002, Proceedings of 5th International Conference on Hydrodynamics, 135 - 140, English
    [Refereed]
    Scientific journal

  • Yoshikazu Kasahara, Tomohiro Asaumi, Tokihiro Katsui
    An efficient hull form design needs to incorporate prediction methods that will be able to predict the influence of hull form modification on the ship performance. This paper presents a simple prediction method for propulsive factors - form factor, wave-making resistance coefficient, thrust deduction coefficient and effective wake coefficient - which relate directly to the hull form. Some flow-field parameters which have influence on the propulsive factor are proposed on the basis of the result of double-model flow calculation, 3-dimensional boundary layer calculation, TUMMAC-IV code and propeller-hull interaction calculation around the hull form. Regression equations to predict propulsive factors are made by using some parameters and model test results in a towing tank..
    By the present regression equation, predicted results for propulsive factors of small-sized tanker that change the fullness in steps are shown. On basis of calculation results, a new hull form that increase the fullness is designed. A new hull form ship is confirmed the same performance of the parent ship by the towing tank test and the present calculation result.
    The Japan Society of Naval Architects and Ocean Engineers, Mar. 2002, Journal of the Kansai Society of Naval Architects, Japan, (237) (237), 55 - 62, Japanese
    [Refereed]
    Scientific journal

  • Keiichi Yamasaki, Satoshi Masuda, Tokihiro Katsui
    This paper describes the application method of CFD (Computational Fluid Dynamics) to the ship manoeuvrability study on the initial stage of hull design. The present method is a method of estimating the linear derivatives of hydrodynamic forces acting on a hull, by using the correlation of CMT (Circular Motion Test) data and CFD computations on two conditions of oblique towing (B=6deg.) and circular motion (r'=rLpp/U=0.2) without drifting angle. Hydrodynamic forces acting on a hull in manoeuvring motion can be calculated by the combination of the linear derivatives obtained by the method mentioned above and the nonlinear ones estimated by CMT database. Authors applied the present method to the estimation of the hydrodynamic forces measured by CMT and the manoeuvring motion at Sea trial, and confirmed its validity.
    The Japan Society of Naval Architects and Ocean Engineers, Jun. 2001, Journal of the society of naval architects of Japan, (189) (189), 55 - 62, Japanese
    [Refereed]
    Scientific journal

  • Kiyoshige Matsumura, Tokihiro Katsui
    Dec. 1999, Journal of Marine Science and Technology, (4) (4), 180 - 186, English
    [Refereed]
    Scientific journal

  • Variational Principle with Unknown Wetted Surface of Planing Ship Considering Gravitational Effect
    Tokihiro Katsui, Kiyoshige Matsumura
    An adjoint variational principle for determination the wetted surface of planing ship considering gravitational effect is proposed based on a principle regardless of gravitational effect. A method of high aspect ratio approximation is investigated. A simple relation is obtained between the Froude number based on the wetted length in running condition and the one based on the still water length. The solution of wetted surface of planning plate agreed with experimental results, compared with the case regardless of gravitational effect.
    Lead, The Japan Society of Naval Architects and Ocean Engineers, Mar. 1999, Journal of the Kansai Society of Naval Architects, Japan, (231) (231), 37 - 47, Japanese
    [Refereed]
    Scientific journal

  • Determination of Wetted Surface of Slender Planing Ship by the Method of Variational Principle
    Tokihiro Katsui, Kiyoshige Matsumura, Shigehisa Hamaguchi, Toshio Suzuki
    Lead, Sep. 1998, Journal of the Kansai Society of Naval Architects, Japan, (230) (230), 133 - 140, Japanese
    [Refereed]
    Scientific journal

  • Tokihiro Katsui, Kiyoshige Matsumura, Toshio Suzuki
    Lead, 公益社団法人日本船舶海洋工学会, Jun. 1998, Journal of the society of naval architects of Japan, (183) (183), 1 - 6, Japanese
    [Refereed]

■ Books And Other Publications
  • 船舶海洋工学シリーズ① 船舶算法と復原性
    池田 良穂, 古川 芳孝, 片山 徹, KATSUI TOKIHIRO, 村井 基彦, 山口 悟
    Joint work, 成山堂書店, Apr. 2012, Japanese
    Textbook

  • 船舶一問一答 これであなたも「船」博士
    村井 基彦, 八木 光, 林 茂弘, 池田 良穂, Tokihiro Katsui, 柴原 正和, 正岡 孝治, 安川 宏紀, 吉川 孝男, 慎 燦益
    Joint work, (株)海事プレス社, Mar. 2006, Japanese
    General book

■ Lectures, oral presentations, etc.
  • 水中クローラROV(Remotely Operated Vehicle)の開発と活用
    KATSUI TOKIHIRO, 井上 朝哉, 大澤 弘敬, 高木 健, 津久井 慎吾, 新堀 貴
    第29回日本ロボット学会学術講演会, Sep. 2011, Japanese, Domestic conference
    Oral presentation

  • ｹｰﾌﾞﾙ張力を考慮したクローラ型ROVの可動範囲解析
    KATSUI TOKIHIRO, 明石 雅成, 井上 朝哉
    日本船舶海洋工学会講演会, 2011, Japanese, Domestic conference
    Oral presentation

  • 砂上を走行するクローラ型ROVの水中走行特性について
    勝井 辰博, 村上 尚隆, 井上 朝哉, 新堀貴
    日本船舶海洋工学会講演会(日本船舶海洋工学会講演会論文集, 第8号, pp.21-24), May 2009, Japanese, 日本船舶海洋工学会, 神戸, Domestic conference
    Oral presentation

  • クローラ型ROVの水中定常走行時における安定走行条件に関する研究
    村上 尚隆, 井上 朝哉, 勝井 辰博
    日本船舶海洋工学会関西支部講演会(日本船舶海洋工学会講演会論文集, 第7K号, pp.41-44), Nov. 2008, Japanese, 日本船舶海洋工学会, 吹田(大阪), Domestic conference
    Oral presentation

  • チャインドライ航走時の滑走艇の浸水面形状と船底圧力分布の数値解析
    勝井 辰博, 片山 徹, 望月 健司
    日本船舶海洋工学会講演会(日本船舶海洋工学会講演会論文集, 第6号, pp.167-168), May 2008, Japanese, 日本船舶海洋工学会, 長崎, Domestic conference
    Oral presentation

  • 実用型滑走艇の航走シミュレーション
    勝井 辰博, 片山 徹
    日本船舶海洋工学会関西支部講演会(日本船舶海洋工学会講演会論文集, 第5K号, pp.107-108), Nov. 2007, Japanese, 日本船舶海洋工学会, 吹田(大阪), Domestic conference
    Oral presentation

  • 滑走艇の定常航走姿勢シミュレーション
    勝井 辰博
    日本船舶海洋工学会講演会(日本船舶海洋工学会講演会論文集, 第3号, pp.247-248), Nov. 2006, Japanese, 日本船舶海洋工学会, 神戸, Domestic conference
    Oral presentation

  • 線図フェアリング自動化に関する基礎的研究
    勝井 辰博, 樋口 誉英
    日本船舶海洋工学会関西支部講演会(日本船舶海洋工学会講演会論文集, 第2K号, pp.173-174), May 2006, Japanese, 日本船舶海洋工学会, 吹田(大阪), Domestic conference
    Oral presentation

  • 主翼独立制御型水中グライダー実験機の設計と開発
    有馬 正和, 豊田 篤史, 住野 亘, 勝井 辰博, 奥野 武俊
    日本船舶海洋工学会関西支部講演会(日本船舶海洋工学会講演会論文集, 第2K号, pp.57-60), May 2006, Japanese, 日本船舶海洋工学会, 吹田(大阪), Domestic conference
    Oral presentation

  • 滑走艇の航走時浸水面形状と流体力推定シミュレーション
    勝井 辰博, 甲滝 昌功
    日本船舶海洋工学会関西支部講演会(日本船舶海洋工学会講演会論文集, 第2K号, pp.169-172), May 2006, Japanese, 日本船舶海洋工学会, 吹田(大阪), Domestic conference
    Oral presentation

  • Development of CFD-Based Multi Objective Optimization Method for Ship Design
    Yusuke Tahara, Satoshi Tohyama, Tokihiro Katsui
    NAPA User Meeting 2005(Proc. NAPA User Meeting 2005, pp.1-21), Jun. 2005, English, NAPA Ltd., Helsinki, International conference
    Invited oral presentation

  • Development of CAD/CFD/Optimizer-Integrated Hull-Form Design System
    Yusuke Tahara, So Sugimoto, Shinya Murayama, Tokihiro Katsui, Yoji Himeno
    NAPA User Meeting 2003(Proc. NAPA User Meeting 2003, pp.1-7), Apr. 2003, English, NAPA Ltd., Helsinki, International conference
    Invited oral presentation

■ Affiliated Academic Society
  • The Kansa Society of Naval Architects, Japan

  • The Society of Naval Architects of Japan

  • 関西造船協会

  • 日本造船学会

■ Research Themes
  • The development of evaluation method for EEXI reduction with low-friction ship bottom paint
    Tokihiro Katsui
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2023 - Mar. 2026, Principal investigator
    本研究は低摩擦型を含む舶用防汚塗料の実船摩擦抵抗を定量的に推定する手法を示すとともに，塗膜粗面の幾何形状パラメタと実船摩擦抵抗を関連付けることを試みるものである。低摩擦型塗料を開発するにあたって重要な問題は二つである。一つは，「どのよう」な塗料がより摩擦抵抗が低いのか，もう一つは，その塗料を実船に用いた場合，既存の塗料に比べて摩擦抵抗が「どれだけ」下がるのか，である。この二つを明らかにすることで、任意の塗料の実船摩擦抵抗を算定する手法を開発し、低摩擦型塗料の効果による実船のEEXI値の低減量を定量的に推定可能とすることを目的とする。令和5年度は9種の塗膜粗面に対して回転円筒試験装置を用いて各種塗膜粗面近傍の流場計測を行うとともに塗膜粗面を塗布した円筒に作用する回転トルクを計測することで各種塗膜粗面の粗度関数を計測した。さらに、既存の砂粗度に対する粗度関数を基礎とした、各種塗膜粗面が持つ粗さの長さスケールの同定を行った。その結果、粗度波長が比較的長い、通常の塗膜や低摩擦型の塗膜に対しては粗度の長さスケールksは粗度高さRcと粗度波長Rsmの比の関数として概ね1つの関数で表現しうることを示した。また、壁関数を用いた粗面平板周りのCFD解析を実施し、粗面の場合は滑面の場合と異なり壁関数の境界条件の与え方によって、摩擦抵抗の算定結果に差があることを確認した。このことは、塗膜粗面を対象とした場合、壁関数の適用にあたっては、モデルパラメタの選択等、境界条件の与え方に注意が必要であることを示唆するものであり、今後、塗膜粗面を対象としたCFD解析法を構築する上で重要な知見を得たと考えている。
    Competitive research funding

  • Understanding drill bit motion through measurement integrated analysis and identifying drilling conditions through machine learning
    Tomoya Inoue, Hiroyoshi Suzuki, Ryota Wada, Yujin Nakagawa, Tokihiro Katsui
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Agency for Marine-Earth Science and Technology, Apr. 2020 - Mar. 2023, Coinvestigator
    We performed theoretical analysis using a mathematical model as well as numerical analysis of drill bit motion and demonstrated its characteristics. We also proposed a method to understand the drilling status via detecting anomalies, understanding geological formations, and predicting sediment properties and core recovery rates using drill bit motion analysis and machine learning. We performed predictions based on data obtained from Chikyu's past cruises. The effectiveness of proposed method was confirmed. Furthermore, with the aim of real-time understanding of the drill bit motion and drilling conditions during drilling operations, we have developed drilling data acquisition and transfer system, and a data integrated analysis method uses drilling data as input to provide the drill bit motion and drilling conditions in real-time. We conducted a practical test of the real-time drill bit analysis during the actual drilling operations and confirmed the method and system.
    Competitive research funding

  • The evaluation method of full-scale ship performance using low-friction ship bottom paint
    Tokihiro Katsui
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2020 - Mar. 2023, Principal investigator
    The present study investigates the roughness function of the painted surface under assumption that painted surfaces are considered to be wavy surfaces. The roughness functions for three kinds of painted surfaces which have different ratio of wave length to wave height were estimated based on a newly developed method using rotating cylinder measurement. The velocity distribution of turbulent boundary layer of the painted rotating cylinder surfaces were measured using laser doppler velocimeter and the rotating torque of cylinders were also measured to estimate the frictional velocity of the painted surfaces. The estimated roughness functions for painted surfaces based on velocity profile and frictional velocity indicate that it is getting lower for the painted surface with lower ratio of wave length to wave height. The shape of roughness functions for painted surfaces is convex at higher roughness Reynolds number and this attitude is quite different from the sand-grain rough surface.
    Competitive research funding

  • Estimation of dynamic behavior of drill pipe for scientific drilling and its validation using measured data in actual drilling operation
    Tokihiro Katsui, Tomoya Inoue
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2017 - Mar. 2020, Principal investigator
    The Stick-Slip and large bending deformation due to Magnus effect are troublesome problems which happens in scientific drilling. In order to clarify the mechanism of Stick-Slip and large deformation, it is necessary to develop a reliable numerical model to estimate drill pipe motion for various drilling conditions. Stick-Slip was estimated using a numerical procedure to solve NDDE (Neutral Delay Differential Equation) and large bendig deformation due to Magnus effect was estimated using ANCF (Absolute Nodal Coordinate Foumulation). The boundary condition at the drill bit part for NDDE equation is estimated from measured top drive torque and calculated Stic-Slip motion was agreed well with measured data of actual drilling. On the other hand, the hydrodynamic forces on drill pipe for calculating bending deformation of the drill pipe are estimated from model experiments and CFD. The estimated bending deformation of the actual drill pipe varied depending on the ocean current conditions.
    Competitive research funding

  • Development of advanced estimation method for hydrodynamic forces acting on the maneuvering motion ships in restricted water area
    Shigeru Nishio, Tokihiro Katsui
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, Apr. 2016 - Mar. 2020, Coinvestigator
    The behavior of hydrodynamic force acting on ships under maneuver operation are investigated, and the characteristics change due to the decrease of water depth / draft ratio or the relative distance from the surrounding boundaries caused by the increase of ship size are clarified. The dependencies to the hull form factors and the behavior of characteristics change under berthing/deberthing operation was focused, and the mechanism of characteristics change was clarified and an evaluation approach to the unsteady case was proposed.
    Competitive research funding

  • Numerical procedure for Stick-Slip of the drill-pipe
    Tokihiro Katsui, Tomoya Inoue
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Kobe University, Apr. 2014 - Mar. 2017, Principal investigator
    The present study investigated a numerical method to analyze the stick-slip of drill pipe by solving the NDDE (Neutral Delay Differential Equation) which is derived from torsional vibration equation. A small-scale model experiment was conducted in a water tank to observe the stick-slip phenomenon, and the result from the analytical model is evaluated with that obtained from the experiments. Additionally, the numerical model is applied for the actual drill pipe in operation. The solutions of the NDDE is depend on the initial history of the solution and some model parameters concerned with the frictional torque on drill bit. The present study investigated the effects of the initial history and the model parameters settings on numerical solutions in detail and presented an procedure to determine the appropriate settings of the initial history and the model parameters by reference to the measured top drive torque.
    Competitive research funding

  • Development of an estimation method of hydrodynamic forces acting on maneuvering motion ships in shallow water
    Nishio Shigeru, KATSUI TOKIHIRO
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, Apr. 2013 - Mar. 2016, Coinvestigator
    The behavior of hydrodynamic forces acting on a ship at lateral motion was investigated. Force measurement in towing tank and numerical simulation on viscous flow field were made, and correlations of hydrodynamic forces with flow field around ships were examined. A large flow pattern change at extreme shallow water case such as water depth/draft ratio H/d<1.20 was observed in model scale, and it causes serious characteristics change of lateral force. Present characteristics change could be caused by the pressure loss at the gap between sea bottom and ship bottom, which may be referred by ‘retaining effect’, and that generates the upstream flow pattern and separation pattern change.
    Competitive research funding

  • Research on improvement of drilling efficiency by establishing surface drilling data-integrated simulation
    INOUE TOMOYA, KATSUI Tokihiro, YAMAMOTO Miki
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Agency for Marine-Earth Science and Technology, Apr. 2012 - Mar. 2015, Principal investigator
    Drill pipe strength evaluation and bit motions including stick-slip are primarily important problems in offshore drilling. Analytical models and evaluation methods for the above were established. However, it contains essentially important analytical conditions and parameters, and there are defined tentatively for the analysis. Equations expressing the unknown conditions and parameters with drilling data therefore are newly derived by expanding the analytical results. Finally, this research suggested a drilling data-integrated simulation which is analysis method with analytical conditions and parameters determined by the surface drilling data acquired onboard drillship.
    Competitive research funding

  • KATSUI Tokihiro, INOUE Tomoya
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, 2011 - 2013, Principal investigator
    The present study develops a method to estimate the moving capability of the crawler driven ROV on the actual sea bottom for the efficient ROV design. A simple method to estimate the moving capability of the crawler ROV was developed by the authors, however the exact estimation on the actual sea bottom was needed. The present study conducted CFD analysis around a ROV model which reproduce the detail of ROV geometry and evaluated the hydrodynamic forces acting on the ROV. The method to estimate the bump-up capability of the crawler ROV was newly developed by focusing on the attitude of reaction acting on the rear crawler. The elastic cable tension force acting on the ROV considering the interruption from the sea bottom was evaluated by a new numerical procedure. Integrating those schemes, a new methods to estimate the moving capability of the crawler driven ROV was developed and it was validated with the model experiments. The estimations agreed well with model experiments.
    Competitive research funding

  • Development of a simulation method for evaluating the planing performance of high speed crafts.
    KATSUI Tokihiro
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Osaka Prefecture University, 2008 - 2010, Principal investigator
    The planing ship performance was usually evaluated by tank test which spends much cost and time. The present study proposed a simulation based evaluation method of planing ship performance which is applicable for hull design. The flow around planing ship was solved with potential flow assumption and the wetted surface area and hull bottom pressure distribution in arbitrary planing attitude including chine dry situation was obtained. Based on the calculated hydrodynamic forces acting on the hull, the planing attitude was estimated. The planing attitudes corresponding to various ship speeds agreed well with experimental results except the lowest speed. The transverse stability in inclined planing condition was also evaluated by numerical simulation and it was agreed with tank tests results qualitatively. In addition, a method to estimate the porpoising (longitudinal instability phenomena) occurrence condition based on the simulation was presented.
    Competitive research funding

  • Development of SBD system for design of high-speed multi-hull ships
    TAHARA Yusuke, TSUBOGO Takashi, KATSUI Tokihiro
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka Prefecture University, 2006 - 2008, Coinvestigator
    本研究の目的は, より高度化されたCFD援用船型最適化手法や, わが国の造船設計に適合したCADインターフェースを統合することによって, 次世代型革新的船型の一つとされる高速複胴船型の最適設計を目的としたシミュレーション・ベースド・デザイン(SBD)手法を完成させることである. 3カ年におよぶ本研究の所期の目標は全て達成され, 学術的・実用的見地において, 国際的にも高レベルな研究成果を得ることができたと考えている.
    Competitive research funding

  • NS方程式に基づく流場逆解析手法の提案と船型改良への適用
    勝井 辰博
    日本学術振興会, 科学研究費助成事業, 若手研究(B), 大阪府立大学, 2005 - 2006, Principal investigator
    本研究課題は,新しい粘性流場の逆解析手法を示し,船型設計の支援ツールとしての応用可能性について検討をおこなったものである。研究最終年度である平成18年度は、平成17年度までに開発を行った2次元流場の逆解析手法の問題点の改善を試みた.計算の対象としたのは2次元キャビティー流れであり,指定した速度場,あるいは圧力場を実現するような境界条件求めることが目標である.本手法は,流場の支配方程式であるNS方程式および連続の式の残差を流場(速度場,圧力場)と形状等の境界条件(ここでは流速境界条件)の関数として捉え,その第一変分が0となるように境界条件と流場を拘束する,随伴方程式を解くことによって逆解析を実行するものである.局所線形化に基づく定式化であるため,目標とする流場を現在の流場から大きく変化させてしまうと非線形影響による誤差が生じることになる.この誤差については,ニュートン法による繰り返し計算によって修正を行っている.この手法は迅速に粘性流場の逆解析を行うことができるという特徴があるものの,特に境界近傍での流場の逆解析を行おうとすると収束性が悪化するという問題を抱えていた.そこで解くべき随伴方程式に高次項を付加し第2近似方程式を構成してこれを解くことにより,計算収束性を向上させることを試みた.その結果,これまでの第1近似随伴方程式を解く方法では,収束解が得られなかったような事例に対しても,本年度開発した第2近似随伴方程式を解く方法では収束解が得られることが示され,粘性流場逆解析手法としての精度向上を達成することができた.これにより本研究課題の研究目標は概ね達成されたと考える.
    Competitive research funding

  • Development of High-Performance CFD Coding Method for PC-Cluster Parallel Computing Environment
    TAHARA Yusuke, HIMENO Yoji, KATSUI Tokihiro
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka Prefecture University, 2002 - 2005, Coinvestigator
    Computational fluid dynamics (CFD) is an important component technology for simulation-based design (SBD), which will play essential role in design of new concept ships in next generation. Since beginning of 1990s, large effort has been directed toward development of higher fidelity CFD approach, i.e., Reynolds-averaged Navier-Stokes (RaNS) equation method with free-surface tracking or capturing capability. In general computational mechanics field, the global trend is moving toward utilization of larger mesh, such that computations with over 1 million grid points will be minimum routine task in very near future. The trend will be more accelerated by recent advancement of information technology (IT) especially for low-end high-performance computing facility, e.g., PC-Cluster parallel computing environment. However, availability of computational mechanics codes which fully utilize the parallel capability is still limited, and that holds true for CFD code in ship hydrodynamics. This is due to a fact that parallel coding technique for recent RaNS method has not matured while compiler-based automatic parallel conversion is often found unsatisfactory. This four-year research project (Year-1 through Year-4) concerns development of large-scale high-performance (LSHP) CFD coding method for PC-cluster parallel computing environment. Main objective of the present study is enhancement of capability of RaNS equation solver and its advanced applications for LSHP computing in ship hull form design. In Year-1, focus was placed on setup. and initial evaluation of the present coding environment. The Message Passing Interface (MPI) protocol and the Score-D job scheduling method were implemented in the present system. Detailed performance evaluation of the system was done for high-performance parallel coding of CFD-based nonlinear programming and a domain-decomposition-based commercial RaNS equation solver. In Year-2 through Year-4, primary focus has been on parallel high-performance coding for author's multi-block RaNS method in association with physical domain decomposition, and CFD-based hull form optimization using a parallel-based non-determinative nonlinear programming. These were successfully completed and the results have been presented in more than 10 conference and international journal papers.
    Competitive research funding

  • 微分幾何に基づく船型CADシステムとCFD間のインターフェースに関する研究
    勝井 辰博
    日本学術振興会, 科学研究費助成事業, 若手研究(B), 大阪府立大学, 2002 - 2003, Principal investigator
    本研究は、微分幾何学に基づいたCADシステムによって作成された船型とそのまわりのCFD解析による流場とを簡潔に結びつけることを目的としている。平成14年度には2次元翼形状を対象とし、簡易的なCADとしてベジェ曲線を用いて翼形状を表現した。その形状パラメタとCFD解析による流場との関係については、随伴変数法を用いて感度解析を行うことにより、迅速に形状と流場を結びつけられることを示した。本年度は、随伴変数法を応用して2次元粘性流場の逆解析手法を構築することを試みた。随伴変数法は流場の支配方程式の性質に着目した効率的感度解析手法である。この手法では、物体周りの流れを考える場合、物体形状と流場がそれぞれ変化したときに生じる支配方程式の残差がお互いキャンセルするように形状変化に対して流場変化を拘束する。この関係は、局所線形化された支配方程式を解くことによって、非常に短時間に求めることができる。逆に流場の変化に対して、形状の変化を拘束することも可能である。このことは、流場の変化を指定したときに、それに対応するような形状が求められることを意味する。これはまさに逆解析そのものである。しかしこれは前述のとおり、局所線形化した方程式に基づく解法であるため、指定する流場変化量を大きくとると、流場に支配方程式の非線形性から、解に誤差を生ずる。この誤差修正には、ニュートン法に準じた繰り返し計算を行う手法を用いた。この手法を2次元キャビティー流れに適用した。具体的には適当な境界条件の下にキャビティー流れを解き、キャビティー内のある点の流速が指定した値となる境界条件を求める逆問題を解いた。その結果、計算格子数が少ない場合については、極めて迅速に逆解析が実行できることを確認した。この手法は物体周りの流れに対しても適用可能であると考えられる。以上の成果をもって、本年度の所期の目的はほぼ全て達成できたと考える。
    Competitive research funding

  • Development of Network-Distributable CFD-Based Optimization System
    HIMENO Yoji, KATSUI Tokihiro, TAHARA Yusuke
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Osaka Prefecture University, 2001 - 2003, Coinvestigator
    The objective of the present research is to develop a network-distributable CFD-based optimization system for general hydrodynamic design. The most important feature of the present system is the compact and network-distributable architecture, which resolves many issues in current usage of IT applications in ship design, i.e., CAD, analysis methods, and optimization methods have been independently developed and the networking interfaces are not well established. In the first year and part of the second year, focus was placed on development of CAD/CFD/Optimizer integrated design system on a standalone server. Then in rest of the second year, the system was extended including the network-distributable architecture so that each module may be located at arbitral computing resource within the same local area network. As a demonstration, a commercial CAD system for ship design, NAPA, was integrated into the present system. The CFD and optimizer modules are a Rakine-source panel method and non linear programming codes based on SQP and GA, all of which were developed by the present investigators. Those tasks were successfully completed, and results presented for a container-ship bow optimization were shown to be very promising. Finally, main effort in the third year (final year) was directed toward further evaluation of the present system and documentation. It was shown that the present system offers advantages to designers who wish to make full use of their IT application resources, which leaded to an important fact that designers have more opportunities to study alternative designs. In conclusion, all tasks of the present work had been successfully completed, and further extension of the present system appeared to be possible in many design applications. In fact, the extension has been currently in progress in collaboration with several IT industries.
    Competitive research funding

■ Industrial Property Rights
  • 水中走行車両およびその制御方法
    KATSUI TOKIHIRO
    特願2009-126012, 26 May 2009, 大学長, 特許5403602, 08 Nov. 2013
    Patent right

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