A simple wave generation method for navier-stokes equations

Abstract

We develop a simple but effective method for generating waves for a 3D Navier-Stokes equation solver of Kang and Sotiropoulos (2012). In this method the waves are generated by imposing a velocity boundary condition at the bottom of the computational domain. The advantage of this method is that it does not require a modification of the governing equations for mass/momentum source terms, which has been widely employed in the existing internal wave generation method. We apply the new method to generate waves in a simple-shaped computational domain and compare the results with benchmark solutions. The comparison suggests that the wave height generated by using the velocity boundary condition is underestimated especially when kh (k: wave number, h: water depth) is large. We propose an empirical correction factor accounting for the reduced mass.