| Summary: | 碩士 === 國立臺灣大學 === 農業工程學研究所 === 88 === It has been investigated experimentally, theoretically and numerically that a forcing disturbance moving steadily with a transcritical velocity in water of finite depth can generate nonlinear waves. As the phenomenon is observed in the disturbance frame, the incident flow comes from the free-stream uniform state with velocity equal to the disturbance. In the present work, the field described above is simulated numerically by solving the vorticity-stream function with fully non-linear boundary conditions specified on free surface. To handle the deformation of physical domain, the Lagrangian-Eulerian kinematic description and the technique of boundary-fitted coordinate are adopted for computation of the free surface flow. For discretization of governing equations and boundary conditions, the finite elementary method and finite difference method are employed, respectively.
To verify the computational model, the results from fKdV model by Wu and experiments by Lee are employed to compare with the present calculation in potential flow and viscous flow, respectively. In the present work, the Froude Number defined by uniform water depth and velocity of inflow is dominant effect on the field. The Reynolds Number is used to predict the generation of the vortex behind the obstacle. However, geometry of the obstacle is an important factor in generation of solitary wave.
|
|---|
