Numerical Study of Radiation Stress on the Submerged Bars by Regular Wave

In the study of nearshore wave, the radiation stress is an important physical quantity which is an excess momentum flow caused by waves. As waves transfer from deep water to shallow water, the nonlinearity of wave increases gradually and waves are deformed or even broken. This will cause strong shift in radiation stress and make significant contributions to the generation of infragravity wave. In this paper, OpenFOAM is used to fine simulate the propagation of waves on the submerged bars. In the case of breaking waves, the detailed flow field information of wave motion is obtained. Besides, the radiation stress and the wave set-up and set-down on the submerged bars terrain are calculated. Numerical results show that the radiation stress value is quite sensitive to the wave amplitude shift at the flat bottom before the submerged bars. When the wave is completely broken, the value of radiation stress increases at the back submerged-bars slope and then it tends to level off at the flat bottom behind the submerged bars. The effect of variation trend of radiation stress along the way on the wave set-up and set-down is in good agreement with the wave set-up and set-down equation.