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

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

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

Lab members: 研究室メンバー紹介

Ryota TSUBAKI/ 椿涼太

Sefat Karimullah (Research associate, Nagoya University)

Noe KIMURA/木村乃依 (M1)：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 (M1)：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

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

Taichi MIYAURA/宮浦太一 (B4)：中山間地と水害

Miku HANIOKA/埴岡光来 (B4)：部分的河道拡幅と通過土砂

Naoya OSHIMA/大島尚也 (B4)：河川の風波

Recent activities

Visited Lausanne and the surrounding area to see river engineering works (August 2026)

Génie civil: Civil engineering in French.

Visited Lausanne, CH, to visit Prof. Govanni at EPFL, and see several river engineering works around the city.

Visited were from mountanious check dam, upstream and middel reach river restroation sites.

Also visited a diving section of the combined sewer system. Running water finally flows into Lake Leman.

Had a meeting at the campus.

The lake is good to see and swim. Wild blackberries were also very fine and fresh.

Participated in IAHR-APD2026 in Inchon (July 2026)

I joined the IAHR-APD2026 held at Inchon, South Korea. Nice venue, hot weather.

I presented a poster on the flume experiment analysing the flow field around the pressure-measuring cobble. Discussion on our and other studies are inspiaring and informative.

During the conference, I met many old and new friends.

Attended the Riverflow2026 in Thessaloniki (June 2026)

I presented "Bedload dynamics in an artificial secondary channel in a braided gravel river", and briefly reported on the field survey conducted a week prior.

With Dr. Manousos. The conference was exceptionally well-organized, and I had a wonderful time.

Many cats in the downtown area. I was afraid of wild dogs, but they are very rare.

Pavement repairs in progress. I found it interesting that the drain gutter is located right in the center of the street. In Japan, drain gutters are built along both side of the road.

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