Aerial photo, Tone River, Japan (September 17, 1998)

Horizontal vortex in open-channel flows

(CFD, shallow water model，contour of vorticity)

Dam-break problem, simulated by the MARS method

(blue: water column, background: air)

Organized motions water flow near the free-surface in air-water co-current flows,

visualized by the hydrogen-bubble method

Lush trees established on gravel bars in the lower reaches of the Asahi River, taken at the left side of the 15 km upstream section from the river mouth in early September, 2012

Numerical results of the Asahi River flood flow in 2012

Hydraulic structures Installed in rivers using natural stones

(left: Maruyama River, Japan; right: Fushino River, Japan).

Installation of the stone model in an experimental flume

and a force transducer fixed to the model

A segmented stone model with multiple tetrahedron elements

Simulation results of instantaneous vorticity behind the stone model at the vertical cross-section; upper left: 1.0s, upper right: 2.0s, lower left: 3.0s, lower right: 4.0s (elapsed time from initial condition)

　

Typical scene of coastal dike failure at the southern part of Sendai’s coast in Miyagi prefecture (left) and construction example of the armored coastal dike using concrete blocks

Figure 10 Flat block model for simulated coastal dikes (left), and landward slope protection works and landward toe protection works in laboratorial experiments.

Overview of computation domain (upper), lateral length scale of the computation domain (lower left), and multigrid system using a nesting technique for simulations in the x–z plane

Comparison of time-series of simulation results of water depth with experimentally

obtained results at the top of landward slope of the simulated coastal dike

Numerical results of instantaneous water body and pressure distribution using Flow3D

ALB measurements made with lasers of two kinds in a river terrain with overland and underwater areas

An aerial photo of the lower Asahi River (left) and corresponding bathymetry contour map made by ALB measurement data

Full-waveform ALB point cloud scattered on both the trees and river bed

Aerial photograph taken on March 3, 2016 (left) and the corresponding land use map (right) processed using ALB data around the bifurcation point of the lower Asahi River

Ayu detection using a deep learning technique (YOLOv5) for underwater camera images

in the Asahi River around the Heidan area (10 KP)

Land cover classification using semantic segmentation (DeepLabV3+) for drone images

in the Asahi River reach around the bifurcation point (12 KP)

Investigation of favorable spawning sites for Ayu fish in the Asahi River estuary, based on a series of field work activities and numerical simulations (AEM 3D) on environemtal factors