Hydrodynamic simulation of fish swimming

Abstract

This project is dedicated to perform 3D simulation for the swimming motion the anguilliform swimmer, by using Computational Fluid Dynamics (CFD) tools. In the project, two major issues are concerned. Firstly, the anguilliform swimming motion is simulated and a parametric study is conducted to find optimal swimming motion patterns. Secondly, the swimming patterns implied by the CFD simulation are implemented on the control of a Kinfefish robot in order to achieve energy-efficient swimming motion. Experiments are conducted to test and refine the simulation. The Gambit software is used to create the 3D fish model. Meshes are also being applied to the 3D fish model in Gambit. The meshes are being applied in the way that the meshes closes to the 3D fish model are the finest and grow larger by 1.2 times until it reaches the wall of the tank. Then the 3D model is imported into the Fluent, a commercial CFD tool, to perform the simulation. The simulations are to simulate the anguilliform motion by using different condition like frequency, amplitude and velocity. The purpose of this simulation is to obtain the net force created by different condition and define the relationship between each condition. Finally, the motions that simulated in software are also implemented on a robotic Knifefish. An experiment had been conducted, the trend of the graph tabulated from the experiment result gather are the same as the simulation. For example when the frequency increases the net force will also increases creating a higher propulsion force, another factor which contributed to the changes of net force were the amplitude, which increases the net force when the amplitude get larger.