Research activity information

• COLREGs-Compliant Distributed Stochastic Search Algorithm for Multi-Ship Collision Avoidance

  Bohan Zhang, Jinichi Koue, Tenda Okimoto, Katsutoshi Hirayama

  Jul. 2025, Journal of Marine Science and Engineering

  Scientific journal


• Topographic Control of Wind- and Thermally Induced Circulation in an Enclosed Water Body

  Jinichi Koue

  Jun. 2025, Geosciences

  Scientific journal


• A Comparative Analysis of Deep Learning Approaches for Visual Perception Benchmarks in Ship Navigation

  Ruolan Zhang, Xingchen Ji, Jinichi Koue, Katsutoshi Hirayama

  Springer Science and Business Media LLC, Apr. 2025, Journal of Marine Science and Application

  Scientific journal


• Investigation of Interfacial Behavior in Density Current Collisions

  Jinichi Koue

  This study provides a comprehensive examination of colliding density currents with a range of density differences from 1% to 4%, using controlled laboratory experiments with saltwater and freshwater. The research reveals that when density currents collide, they generate internal bore, with the denser fluid flowing consistently beneath the lighter fluid. A significant finding is the temporary stalling and oscillatory motion of the current fronts during collisions, which is linked to a partial dissipation of kinetic energy and the subsequent formation of internal waves. Numerical simulations showed close agreement with experimental observations, reproducing the location of the tidal fronts well and verifying the accuracy of the hydrodynamic model used. Moreover, the study demonstrates that collisions between fluids with different densities notably enhance diffusion and mixing efficiency. This has important implications for environmental science, particularly in understanding and predicting density-driven fluid dynamics in aquatic systems such as estuaries and coastal zones. The enhanced mixing efficiency observed could be crucial for applications in environmental and pollution control, offering insights into material transport and pollutant dispersion.

  MDPI AG, Feb. 2025, Journal of Marine Science and Engineering, 13(2) (2), 363 - 363

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Influence of Nutrient Desorbed from Sediments and Density Variations Driven by Organic Matter on Flow Patterns in Closed Water Bodies

  Jinichi Koue

  Jan. 2025, Water

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Impact of riverine inputs on nutrient dynamics and water quality in enclosed water bodies

  Jinichi Koue

  AbstractThis study investigates the intricate dynamics of nutrient transport and stratification in Lake Biwa, highlighting the significant impact of river inflows on water quality. Utilizing a validated three-dimensional flow field model and ecosystem model including a bottom sediment model, the analysis revealed that nutrient concentrations, specifically NH₄⁺, NO₂⁻, NO₃⁻, and PO₄3⁻, exhibited pronounced seasonal variations. In the RN_double scenario, NH₄⁺ and NO₂⁻ concentrations demonstrated a slight increase of 0.1 µg/L, respectively, while NO₃⁻ concentrations rose by 0.05–0.10 µg/L in response to precipitation changes. Conversely, in the RN_half scenario, NH₄⁺ and NO₂⁻ concentrations decreased, with NO₃⁻ seeing a more substantial decline of approximately 0.1 µg/L, attributed to reduced precipitation. PO₄3⁻ levels exhibited a maximum decrease of 0.03 µg/L from summer to autumn. Furthermore, simulations limiting nutrient inflows indicated a modest reduction in concentrations: NH₄⁺ decreased by approximately 0.03 µg/L during summer, and NO₂⁻ decreased by around 0.05 µg/L from spring to summer. The results suggest that while immediate improvements in dissolved oxygen levels are limited, effective long-term nutrient management could stabilize oxygen concentrations and improve overall water quality. These findings underscore the necessity for comprehensive water management strategies to mitigate eutrophication effects and support the ecological health of Lake Biwa.

  Dec. 2024, Terrestrial, Atmospheric and Oceanic Sciences, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Analysis of the Effects of Differently Shaped Embankments on the Density Current

  Jinichi Koue

  Density currents, fluid flows driven by differences in density, play a crucial role in disaster prevention for water pollution and tsunami mitigation, particularly due to thermal releases from power plants. Understanding their dynamics is pivotal for effective mitigation strategies. While the influence of seabed and lake bottom topography on density currents is well-studied, research on how embankment shapes affect these currents has been limited. This study aimed to fill this gap by experimentally and numerically analyzing the flow dynamics of density currents using various embankment shapes in a controlled water tank environment. The findings revealed distinct variations in density perturbation across different embankment shapes. Specifically, density currents exhibited reduced head velocities in embankments shaped as right-angled triangles, rectangles, and L-shapes, in that sequential order. This research underscores the significance of embankment design in modifying density currents, offering valuable insights for optimizing disaster management strategies related to water pollution and tsunami hazards induced by thermal effluents from industrial sources.

  Nov. 2024, Water, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Examining Characteristics of Cavitation Jets and Their Effects on Removing Sessile Organisms

  Akihisa Abe, Jinichi Koue

  Jul. 2024, Marine Engineering, English

  Scientific journal


• Development of an Ecosystem Model Considering Sediment Redox Processes in Enclosed Water Bodies

  Jinichi Koue

  Jul. 2024, Water (Switzerland), 16(13) (13)

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Experimental Investigation of Underwater Noise Generation Mechanism During Pile Driving

  Jinichi Koue, Saori Shyu, Akihisa Abe

  International Society of Offshore and Polar Engineers, Mar. 2024, International Journal of Offshore and Polar Engineering, 34(1) (1), 93 - 100

  [Refereed]

  Scientific journal


• Behavior Analysis of Cavitation Jets for Effective Removal of Organisms Attached to Offshore Structures

  Jinichi Koue, Satoshi Onishi, Akihisa Abe

  International Society of Offshore and Polar Engineers, Mar. 2024, International Journal of Offshore and Polar Engineering, 34(1) (1), 67 - 74

  [Refereed]

  Scientific journal


• Assessing the impact of climate change on dissolved oxygen using a flow field ecosystem model that takes into account the anaerobic and aerobic environment of bottom sediments

  Jinichi Koue

  2024, Acta Geochimica

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Modeling the Effects of River Inflow Dynamics on the Deep Layers of Lake Biwa, Japan

  Jinichi Koue

  Abstract Climate change-induced extreme weather events, including prolonged droughts and intense rainfall, exert a significant influence on river inflows. These inflows act as vital conduits for nutrient transport, water quality modulation, and the regulation of thermal dynamics in lakes and oceans. In this context, this study conducts a comprehensive examination of the multifaceted effects stemming from river water characteristics, snowmelt water influence, and shifts in precipitation patterns on the stratification dynamics of Lake Biwa in Japan. To facilitate these investigations, a hydrodynamic model was developed to simulate thermal stratification in Lake Biwa. The results demonstrate that an increase in precipitation and river water flow, specifically doubling these factors, leads to noticeable cooling of the lake’s surface layer and a consequent destabilization of stratification during the stratification period. Conversely, halving these factors stabilizes stratification. Furthermore, elevating river water temperature by 5 °C raises water temperature near the upper thermocline, encouraging vertical mixing within the surface layer. Conversely, a 5 °C decrease induces significant temperature fluctuations and an unstable stratification extending from the surface to deeper layers. Notably, the spatial variance in water temperature within Lake Biwa is profoundly influenced by fluctuations in river water temperature. This study underscores the critical importance of considering river plumes in the study of material circulation, stratification dynamics, and ecological well-being in lakes and oceans. Given the mounting concerns related to eutrophication and the prevalence of anoxia in aquatic ecosystems, this research provides invaluable insights into assessing the impacts of river plumes on Lake Biwa’s stratification structure and seasonal dynamics.

  Springer Science and Business Media LLC, Dec. 2023, Environmental Processes, 10(4) (4)

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Effect of wall friction on oscillation of velocity at the head of the gravity current

  Jinichi Koue

  May 2023, Theoretical and Applied Mechanics Letters, 100439

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• EFFECTS OF STRONG WINDS ON THE BOTTOM LAYER DURING THE WEAK STRATIFICATION PERIOD IN LAKE BIWA, JAPAN

  Jinichi Koue

  Apr. 2023, International Journal of GEOMATE, Vol. 24(104), 44 - 52

  [Refereed]


• DYNAMIC EFFECTS OF THE HEAD EDGE BEHAVIOR OFGRAVITY CURRENT

  Jinichi Koue

  Mar. 2023, International Journal of GEOMATE, Vol. 24(103), 128 - 135

  [Refereed]


• Analysis of the effects of climate change on the gyre in Lake Biwa, Japan

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  Abstract The currents of gyre (circulation) flow play an important role in the transportation and mixing of dissolved or suspended nutrients and chemical substances. In recent years, the climate change has affected the flow field in Lake Biwa. However, how much the climate change can influence the flow field has not been clarified enough yet. In the present study, using a three-dimensional hydrodynamic model, we investigated the effect of changes in air temperature, wind speed, and precipitation on the change of the flow field in Lake Biwa. For sensitivity analysis, numerical simulations were performed for a baseline case using realistic meteorological data from 2007 to 2012, as well as hypothetical cases using meteorological data. The analysis revealed that the change in air temperature and precipitation changed stratification and vorticity in the surface layer in each season. The strength of the stratification affected the gyre strength in the surface layer. The change in wind speed, on the other hand, changed the wind stress acting on the lake's surface, influencing the strength of gyre significantly. Increased wind speed lengthened the radius of the gyre in Lake Biwa, while decreased wind speed made it weaker above and below the thermocline.

  IWA Publishing, Mar. 2023, Journal of Hydroinformatics

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• STUDY ON THE ANALYSIS OF THE CONTROLLING FACTORS OF HYPOXIA IN THE BOTTOM OF LAKE BIWA, JAPAN

  Jinichi Koue

  Feb. 2023, International Journal of GEOMATE, 24(102) (102), 101 - 108

  [Refereed]


• EFFECT OF BOTTOM WALL FRICTION ON THE TRANSITION OF DEVELOPMENTAL STAGES OF GRAVITY CURRENT

  Jinichi Koue

  Jan. 2023, International Journal of GEOMATE, 24(101) (101), 11 - 117

  [Refereed]

  Scientific journal


• Evaluation of the Impact of Meteorological Factors on the Stratification of Structure in Lake Biwa, Japan

  Jinichi Koue

  Jan. 2022, HYDROLOGY, 9(1) (1), English

  [Refereed]

  Scientific journal


• NUMERICAL SIMULATION FOR SEASONAL AND INTER-ANNUAL CHANGE OF DISSOLVED OXYGEN IN LAKE BIWA, JAPAN

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  Feb. 2020, INTERNATIONAL JOURNAL OF GEOMATE, 18(66) (66), 56 - 61, English

  [Refereed]

  Scientific journal


• Numerical Analysis of Sensitivity of Structure of the Stratification in Lake Biwa, Japan by Changing Meteorological Elements

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  Climatic factors such as air temperature and wind speed can affect the structure of stratification in Lake Biwa. In general, the rise in air temperature and the decrease in wind speed weaken the vertical mixing and strengthen the structure of the stratification, which interrupts the transport of the substances. However, how much the change of each climate element can influence the structure of the stratification is not clarified. Therefore, it is important to evaluate the effects of each element on the stratification quantitatively. In the present study, we investigated the effect of the change in air temperature and wind speed on the seasonal change of stratification in Lake Biwa by using a three-dimensional hydrodynamic model. Numerical simulations were carried out for a baseline case using realistic meteorological data from 2007 to 2012 and hypothetical cases using meteorological data with modified air temperature or wind speed for sensitivity analysis. The analysis showed that the increase and decrease in air temperature changed the vertical water temperature uniformly in almost all layers. Thus, the strength of the stratification is hardly changed. The increase and decrease in wind speed, however, altered the water temperature near the surface of the lake, so that it significantly influenced the stratification. The increase in wind speed made the water parcels of the surface layer well mixed, and the decrease in wind speed made the mixed layer thinner.

  MDPI AG, Oct. 2018, Water, 10(10) (10), 1492 - 1492

  [Refereed]

  Scientific journal


• Evaluation of thermal stratification and flow field reproduced by a three-dimensional hydrodynamic model in Lake Biwa, Japan

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  MDPI AG, Jan. 2018, Water (Switzerland), 10(1) (1), English

  [Refereed]

  Scientific journal


• Numerical assessment of the impact of strong wind on thermal stratification in lake Biwa, Japan

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  GEOMATE International Society, 2018, International Journal of GEOMATE, 14(45) (45), 35 - 40, English

  [Refereed]

  Scientific journal


• Reproducibility for seasonal and inter-annual thermal stratification in Lake Biwa

  Koue Jinichi, Shimadera Hikari, Kondo Akira

  In recent years, the dissolved oxygen at the bottom of the Lake Biwa has been decreasing. It is considered that the decrease in precipitation (about 100 mm), the rise in temperature (about 1 or 2 Celsius degree), and the decrease in wind speed (about 5 %) during the past 20 years leads to this phenomena. In particular, the rise in air temperature and the decrease in wind speed weakens the vertical mixing, and it may cause the reason of low oxygenation at the bottom layer.
  In our present study, we show that we can reproduce the seasonal and inter-annual change of the structure of water stratification with developing the 3-dimensional hydrodynamic model. This model can reproduce the observed vertical water distribution in order to elucidate how the change of the stratification due to global warming will influence the low dissolved oxygen in Lake Biwa in the future.

  THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES, 2016, Proceedings of 2016 Annual Conference, Japan Society of Hydrology and Water Resources, 29, 21 - 21, Japanese

  [Refereed]


• Structure of the Head of Gravity Currents in a Long Channel

  Jun. 2009, International Offshore and Polar Engineering

  [Refereed]


• 密度界面の不連続性における数値振動を抑制するスキームの開発

  Nov. 2008, 日本船舶海洋工学会 関西支部秋季講演会

  [Refereed]

• Study on Underwater Wave Phenomena and Bubble Formation Induced by Impact Bending of Bar Materials in Contact with the Water Surface

  Akihisa Abe, Jinichi Koue, Takehiro Fujimoto

  The 35th International Symposium on Shock Waves (ISSW35), Jul. 2025


• Study on Confined Cavitation Jet Behavior with Underwater Shock Waves for Removal of Marine Sessile Organisms

  Jinichi Koue, Akihisa Abe, Haruo Mimura

  The 35th International Symposium on Shock Waves (ISSW35), Jul. 2025


• 河口部における流況制御が琵琶湖の水質環境に与える影響の解析

  川村竜斗, 公江仁一

  The 59th Annual Conference of JSWE, Mar. 2025


• 平板間隙内キャビテーション噴流の衝撃波生成に関する研究

  公江仁一, 阿部晃久, 三村治夫

  2024年度衝撃波シンポジウム, Mar. 2025


• 放電誘起キャビテーション噴流の衝撃波生成特性に関する研究

  公江仁一, 阿部晃久

  2024年度衝撃波シンポジウム, Mar. 2025


• 金属棒材の打撃で誘起される水中衝撃波動と気泡生成挙動に関する研究

  阿部晃久, 公江仁一, 藤本岳洋

  2024年度衝撃波シンポジウム, Mar. 2025


• Consideration of the Impact of River Inflows on Nutrient Dynamics and Water Quality in Enclosed Water Area

  Jinichi Koue

  The 14th International Conference on Geotechnique, Construction Materials and Environment, GEOMATE,, Nov. 2024


• 閉鎖性水域における底泥の栄養塩・有機物濃度による密度変化の影響

  公江仁一

  土木学会 第52回環境システム研究論文発表会, Nov. 2024


• Investigation on shock wave phenomena generated around a rod loaded to axial impact in water

  Jinichi Koue, Saori Shu, Akihisa Abe

  2023年度衝撃波シンポジウム, Mar. 2024


• Consideration for Utilizing Shock Waves Generated by Cavitation-jets to Remove Marine Organisms

  Akihisa Abe, Jinichi Koue

  2023年度衝撃波シンポジウム, Mar. 2024


• 先端形状が異なる飛翔体の水中貫入による速度減衰効果の考察

  宮下晃, 公江仁一, 阿部晃久

  高速度イメージングとフォトニクスに関する総合シンポジウム, Dec. 2023


• Exploring the Dynamics of River Inflow and its Effects on the Deep Layer of Lake Biwa through Numerical Simulations

  Jinichi Koue

  13th International Conference on Geotechnique, Construction Materials and Environment, Nov. 2023


• Generation and behavior of underwater shock waves and microbubbles produced by metal plate discharge

  Jinichi Koue, Akihisa Abe

  The 34th International Symposium on Shock Waves (ISSW34), Jul. 2023


• Experimental analysis of underwater noise produced by impacted bars

  Jinichi Koue, Saori Shyu, Akihisa Abe

  23rd International Offshore and Polar Engineering Conference, Jun. 2023


• Compressible hydrodynamic consideration of cavitating jets on the scraping action of organisms attached on marine structures

  Jinichi Koue, Satoshi Onishi, Akihisa Abe

  23rd International Offshore and Polar Engineering Conference, Jun. 2023


• 水中衝撃波と弾性膜の干渉によるOHラジカルの生成効果

  山下 理央, 公江 仁一, 阿部 晃久

  2022年度衝撃波シンポジウム, Mar. 2023


• 先端形状が異なる飛翔体の水中貫入に伴う周囲流れの解析

  平井 龍志, 公江 仁一, 阿部 晃久

  2022年度衝撃波シンポジウム, Mar. 2023


• 金属板を介した水中放電による衝撃波と微小気泡生成

  丸山 泉輝, 公江 仁一, 阿部 晃久

  2022年度衝撃波シンポジウム, Mar. 2023


• Analysis of Seasonal and Interannual Variations in Dissolved Oxygen Concentration at the Bottom of Lake Biwa, Japan

  Jinichi Koue

  8th International Conference on Structure, Engineering and Environment, Nov. 2022


• 付着物除去効果向上のためのキャビテーション噴流挙動の観測と解析

  大西智士, 公江仁一, 阿部晃久

  第92回（令和４年）マリンエンジニアリング学術講演会, Oct. 2022


• 洋上風車パイル打設時の水中騒音発生メカニズムに関する研究

  鄒 思織, 宮下 晃, 公江 仁一, 阿部 晃久

  第92回（令和４年）マリンエンジニアリング学術講演会, Oct. 2022


• Formation of metal carbide by electrochemical reduction of CO2 in molten LiCl-KCl

  Fukuda Haruka, Yamada Atsushi, Koue Jinichi, Suzuki Yuta, Goto Takuya, Isogai Tomohiro, Yamauchi Akiyoshi, Kishikawa Yosuke

  The 53th Symposium on Molten Salt Chemistry, Nov. 2021


• Electrochemical Behavior of CO2 reduction in a phosphonium-based ionic liquid

  Tchorap-Yamamoto Shoma, Koue Jinichi, Suzuki Yuta, Kobatake Hidekazu, Goto Takuya, Isogai Tomohiro, Yamauchi Akiyoshi, Kishikawa Yosuke

  The 53th Symposium on Molten Salt Chemistry, Nov. 2021


• Electrochemical reduction of CO2 in [DEME][BF4] containing H2O, The 53th Symposium on Molten Salt Chemistry

  Kozasa Kentaro, Koue Jinichi, Suzuki Yuta, Goto Takuya, Isogai Tomohiro, Yamauchi Akiyoshi, Kishikawa Yosuke

  The 53th Symposium on Molten Salt Chemistry, Nov. 2021


• Effect of change of each meteorological element on the circulation in Lake Biwa, Japan

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  ECSA 58 - EMECS 13 Estuaries and coastal seas in the Anthropocene, Sep. 2021


• Numerical simulation for seasonal and inter-annual change of dissolved oxygen in Lake Biwa, Japan

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  9th International Conference on Geotechnique, Construction Materials and Environment, Nov. 2019


• Individual difference in skin blood flow with air temperature variation

  Otsuka Y, Maeda T, Shiochi S, Matsuo T, Shimadera H, Koue J, Kondo A

  International Workshop on Environmental Engineering 2019, Jun. 2019


• Sensitivity Analysis of Structure of the Stratification in Lake Biwa by Changing Meteorological Elements

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  Conference: 17th world lake conference, Oct. 2018


• Numerical assessment of the impact of strong wind on thermal stratification in Lake Biwa

  Jinichi Koue, Hikari Shimadera, Tomohito Matsuo, Akira Kondo

  7th International Conference on Geotechnique, Construction Materials and Environment, Nov. 2017


• 琵琶湖における成層構造の季節経年変動の再現性

  公江仁一, 嶋寺光, 近藤明

  水文・水資源学会, Sep. 2016


• 琵琶湖流動場モデルによる温度成層の再現性評価

  公江仁一, 近藤明, 嶋寺光, 武川さゆみ, 劉彦妮

  空気調和・衛生工学会近畿支部学術研究発表会, Mar. 2016


• Structure of the Head of Gravity Currents in a Long Channel

  Jinichi Koue, Takuya Katayama, Testuo Katsuragi, Nobuhiro Baba, Kenichi Kitaura

  19th International Offshore and Polar Engineering Conference, Jun. 2009


• 密度界面の不連続性における数値振動を抑制するスキームの開発

  公江仁一

  日本船舶海洋工学会 関西支部秋季講演会, Nov. 2008

• 水環境学会


• 衝撃波学会


• 電気化学会


• マリンエンジニアリング学会


• 土木学会


• 水文水資源学会


• 日本船舶海洋工学会

• Construction and assessment of a sustainable water circulation system in a closed water body using gyres and internal waves

  公江 仁一

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists, Kobe University, 01 Apr. 2024 - 31 Mar. 2027


• Elucidation of the removing mechanism of marine organisms stuck to structure using cavitation jets and development of a nozzle expanding the removal effect area

  阿部 晃久, 藤本 岳洋, 公江 仁一, 三村 治夫

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2023 - 31 Mar. 2027


• 閉鎖性水域の貧酸素化の解消改善方法の提案

  公江仁一

  環境再生保全機構, 環境研究総合推進費, 神戸大学, Apr. 2023 - Mar. 2026, Principal investigator


• 気候変動と富栄養化が閉鎖性水域に及ぼす影響評価

  公江仁一

  ひょうご科学技術協会, 学術研究助成金, 神戸大学, Apr. 2023 - Mar. 2024, Principal investigator

• 一酸化炭素、又は有機化合物の製造方法

  後藤 琢也, 公江 仁一, 鈴木 祐太, 小笹 健太郎, 野崎 紗矢, チョラプ山本笙真, 磯貝 智弘, 岸川 洋介, 山内 昭佳

  特願2022-019162, 10 Feb. 2022, 特開2022-123865

  Patent right


• METHOD FOR MANUFACTURING CARBON MONOXIDE OR ORGANIC COMPOUND

  GOTO Takuya, KOUE Jinichi, SUZUKI Yuta, KOZASA Kentaro, NOZAKI Saya, TCHORAP-YAMAMOTO Shoma, ISOGAI Tomohiro, KISHIKAWA Yosuke, YAMAUCHI Akiyoshi

  特願PCT/JP2022/005415

  Patent right