This section introduces simulation models developed through our previous research.
Simulation of Underwater Bubble Motion
Aeration systems are sometimes used in reservoirs to promote vertical water circulation. These systems release air bubbles from the bottom of the reservoir. As the bubbles rise, they induce upward water flow, promoting vertical mixing.
To quantitatively evaluate how effectively rising bubbles transport the surrounding water upward, we conducted numerical simulations of bubble motion in water.
Because bubble behavior is strongly influenced by surface tension, our simulation model combines three-dimensional fluid flow analysis with the Level Set method to track the shape of the bubble surface. Surface tension forces, which depend on the local curvature of the bubble interface, are also incorporated into the calculations.
Simulation of Rockfall from Glaciers
This research was conducted primarily by a student who had returned from studying abroad in Switzerland.
As global warming causes temperatures to rise, rockfalls involving rocks previously embedded in glacier ice are becoming an increasing concern.
In this study, we developed a simulation model that simultaneously calculates heat conduction from the atmosphere into glacier ice and the melting process in which ice transforms into liquid water.
As the ice (green) melts into water (blue), the rocks (red) lose their mechanical support from the surrounding ice, eventually causing them to fall.
Simulation of Liquefied Soil Flow
In this study, we modeled soil liquefied by earthquake-induced ground shaking as a non-Newtonian fluid and simulated the collapse of structures located along the coastline.
Simulation Using the Discrete Element Method (DEM)
This study demonstrates the use of the Discrete Element Method (DEM) to simulate the motion of large numbers of particles.
In the example below, we analyzed the mixing process inside a bio-toilet, which uses sawdust to decompose human waste. The sawdust and waste were represented by several million individual particles, and their motion during mixing by a rotating agitator was simulated.
The example below demonstrates a simulation of soil compaction in saturated ground. Soil particles are represented using the Discrete Element Method (DEM), which is coupled with a fluid flow simulation of groundwater movement.