Ryota TSUBAKI / 椿涼太

Dr. (Eng.) / 博士(工学)

Associate Professor, Department of Civil Engineering, Kobe University, Japan

神戸大学大学院市民工学専攻准教授

Publons/Web of Science Link

Google Scholar Link

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For inquiry to Ryota TSUBAKI, use the inquiry form.

Research interest: 研究テーマ

High-resolution inundation flow simulation and its application to mitigate physical and environmental risks: 高解像洪水氾濫流解析と、その解析で評価される洪水氾濫流の水理特性に着目した物理的被害や環境への影響の評価と緩和

Keywords: LiDAR, DEM, Finite volume method, Unstructured grid, railway, urban, mountainous

Advanced field monitoring of fluid flow and sediment transport in flooding rivers: 洪水中の河川の流れ・土砂・物質輸送の実測方法の開発と発展

Keywords: Flow visualization, acoustic, pressure, sediment transport, turbulence, gravel bed rivers

Understanding the development process of river geomorphology and managing river geomorphology by utilizing natural processes: 河川の地形変化の予測と制御

Keywords: Gravel bed rivers, vegetation, numerical simulation

Lab members: 研究室メンバー紹介

Ryota TSUBAKI/ 椿涼太

Koki TSURUNAGA/鶴長晃樹 (B4)：過去から現在に至る河道地形および河川生物生息環境の中長期実態分析

Noe KIMURA/木村乃依 (B4)：流砂環境の再生のための自己調節型の土砂供給システムに関する基礎的研究

Maho ISHIHARA/石原真歩 (B4)：中小洪水による網状礫河川の形状変化制御に向けた流速分布計測の現地計測方法の確立

Recent activities

2025/12/19に第47回東海陸水談話会を椙山女学園大学で開催しました

矢作川研究所の内田朝子さんに話題提供いただきました．「川の健康診断の新技術」の演題で，河川の呼吸の計測技術に関する話題を提供していただきました．

2025/12/10-12に福島県郡山市で開催された水工学講演会に参加しました

セッションを運営を一件，いくつかの打ち合わせなどを行っていました．

日本大学の梅田先生，福島大学の川越先生をはじめ現地のみな様，運営ありがとうございます．

安積疏水（あさかそすい）の記念の滝が会場近くの公園にあり，その様子を見てきました．最終日の風がとてもつよく，とばされそうになりました．

2025/11/21-22に京都大学防災研究所と木津川水制群の見学にいきました

21日の午前中は博士課程学生の研究発表の聴講を行い，午後は，会議への参加とセミナーでの話題提供を行いました．

木曽川の水制は樹木群と一体化しつつありました．

Sameh先生，小林先生，現地見学のご案内ありがとうございました．

2025/11/10に旭川で開催された勉強会と現地見学会に参加しました

石狩川の流量観測地点の現地調査を行いました．

見学前に現場近くの「山の食房」で「きのこ丼」をいただきました．きのこが地域の名産だそうです．

Participated in the 8th China-Japan-South Korea Water Science Forum at Kumamoto University on Oct. 30-31, 2025

The forum was organized by Prof. Cho at Kumamoto University. It featured a good venue, informative talks, and good hospitality. This event facilitated valuable research exchanges between Japanese, Chinese and Korean researchers.

Eat Kumamoto Ramen at Kumamoto.

Huge Kumamon at Kumamoto Station．

2025/9/17~19に開催された日本流体力学会年会2025@大阪公立大学に参加しました.

大阪公立大学中百舌鳥キャンパスは，御堂筋線の終点でアクセスに便利で広いキャンパスでした．

普段の水工水理学分野と異なる，機械工学や物理学での流体研究の動向を感じることができました．

浮子流量観測に関する研究経過の報告も１件おこないました．

Participated in the 7th Korea-Japan-Malaysia Mini-Symposium on Modeling and Measurement in Hydraulics at Kampar, Malaysia on June 27-28, 2025.

Presentation by Prof. Choi at Yonsei Univ.

On the way from Singapore to Kampar, we enjoyed the view of the countryside of Malaysia.

Small creek in Kampar's old city.

More recent activities

Study supervision

Funding and research proposal of master's, doctoral and post-doctoral studies

Hiring master's and doctoral students for research projects is not very common in labs in Japanese universities.

Those interested in joining us will either have to pay your expenses or apply for a scholarship. Scholarships are either private or public.

For post-doctoral study, JSPS provides postdoctoral fellowships.

Self-driven research projects are quite important in master's and especially doctoral course. Accordingly, the research proposal by the applicant is quite important. I can advise but the proposal must be prepared by the applicant.

To consult on the master, doctoral, and post-doctoral studies, send your research proposal and C.V. by e-mail.

Description of selected papers

Image motion analysis of sediment particles migrating on dunes

Tsubaki, R., Baranya, S., Muste, M. and Toda, Y.: Spatio-temporal patterns of sediment particle movement on 2D and 3D bedforms, Experiments in Fluids, Vol. 59, No. 93, 2018. Post-print, View-only-version.

Flood Risk Assessment of the Middle Reach of the Helmand River, Afghanistan

K Sefat, R Tsubaki: Flood Risk Assessment of the Middle Reach of the Helmand River, Afghanistan, Journal of Disaster Research 19 (2), 455-464, 2024. Journal link.

A glacial lake outburst flood risk assessment for the Phochhu river basin, Bhutan

T Wangchuk, R Tsubaki: A glacial lake outburst flood risk assessment for the Phochhu river basin, Bhutan, Natural Hazards and Earth System Sciences 24 (7), 2523-2540, 2024. Journal link.

Effects of vegetation distribution along river transects on the morphology of a gravel bed braided river

R Zhu, R Tsubaki, Y Toda: Effects of vegetation distribution along river transects on the morphology of a gravel bed braided river, Acta Geophysica, 72 (2), 1097-1112, 2024. Journal link.

Impact Assessment of Flushing Flow from a Dam to Invasive Aquatic Plant Egeria densa in a Gravel-bed River

R Tsubaki, Y Kawahara, Y Mizuguchi: Impact Assessment of Flushing Flow from a Dam to Invasive Aquatic Plant Egeria densa in a Gravel-bed River, KSCE Journal of Civil Engineering 28 (3), 1062-1074, 2024. Journal link.

Experiment to clarify the condition of railway embankment scour

Tsubaki, R., Kawahara, Y. and Ueda, K.: Railway embankment failure due to ballast layer breach caused by inundation flows, Natural Hazards, Vol. 87, No. 2, doi: 10.1007/s11069-017-2789-3, 2017, Post-print, Journal link.

Fragility curve for railway embankment scour

Tsubaki, R., Bricker, J.D., Ichii, K. and Kawahara, Y.: Development of fragility curves for railway embankment and ballast scour due to overtopping flow, Natural Hazards and Earth System Sciences, EGU, Vol. 16, 2455-2472, doi:10.5194/nhess-16-2455-2016, Paper.

Sediment budgeting using detailed bathymetry maps: Acoustic mapping velocimetry (AMV)

Muste, M., Baranya, S., Tsubaki, R., Kim, D., Ho, H., Tsai, H. and Law, D.: Acoustic mapping velocimetry, Water Resources Research, Vol. 52, doi: 10.1002/2015WR018354, 2016.5, Journal link, Paper.

Spatial interpolation of river ADCP data

Tsubaki, R., Kawahara, Y., Muto, Y. and Fujita, I.: New 3-D flow interpolation method on moving ADCP data, Water Resources Research, Abstract, Paper, Repository

Development of image based flow measurement method and utilization to open water flow analysis

Multi-camera large-scale particle image velocimetry

Tsubaki, R.: Multi-camera large-scale particle image velocimetry. Measurement Science and Technology, doi: 10.1088/1361-6501/ab85d5, 2020, Post-print, Journal link.

On the Texture Angle Detection Used in Space-Time Image Velocimetry

Tsubaki, R.: On the Texture Angle Detection Used in Space-Time Image Velocimetry (STIV), Water Resources Research, Vol. 53(12), doi: 10.1002/2017WR021913, pp.10908-10914, 2017, Post-print, Journal link.

Smartphone apps for river flow measurement (LSPIV apps for iOS and Android)

Tsubaki, R., Fujita, I., Yu, K. and Muste, M.: Large-scale particle image velocimetry (LSPIV) implementation on smartphone, Proceedings of 36th IAHR congress, ISBN: 978-90-824846-0-1, Paper number 3874 on WEB site, Hague, Netherlands, June 28, 2015. Link

Innovation on river monitoring and its application on eco-hydraulics assessment

Development and refinement of methods for measuring water and sediment flow during floods, and assessment of those impact of river ecosystem (riparian and aquatic plants and attached algae)

Compact geophone

Tsubaki, R., Kawahara, Y., Zhang, X and Tsuboshita, K.: A new geophone device for understanding environmental impacts caused by gravel bedload during artificial floods, Water Resources Research, Vol. 53, doi: 10.1002/2016WR019726, 2017, Journal link, Paper, Post-print.

Flood inundation flow modeling

Railway embankment overtopping

Uncertainty assessment of the calculated result

Tsubaki, R. and Kawahara, Y.: The uncertainty of Local Flow Parameters During Inundation Flow Over Complex Topographies with Elevation Errors, Journal of Hydrology, Vol.486, 2013. Journal link, Repository

Mesh generation using LiDAR data

Tsubaki, R., Fujita, I.: Unstructured grid generation using LiDAR data for urban flood inundation modelling, Hydrological Processes, Vol. 24, No. 11, pp. 1404-1420, 2010, Abstract, Paper, Repository

Investigation of flow in a channel in Japanese garden

Tsubaki, R., Nakayama, Y. and Fujita, I.: The design secret of Kyokusui-no-En's meandering channel, Journal of Visualization, Vol. 11, No. 3, pp. 265-272, 2008.7. Abstract, Repository

Ryota TSUBAKI / 椿 涼太