The Interaction Of The Waves And Submarine Sand Bar Topography

In this paper, the physical experiment and numerical simulation based on the Volume of Fluid (VOF) method to solve turbulent governing equations in the numerical wave tank are conducted to investigate the interaction between surface waves and sandbars on the seabed. In the physical experiments, two incident wave heights, fifteen wave periods and four different boundaries on the end of the wave tank are selected for both plain and sinusoidal sandbar topography. The sinusoidal sandbar topography includes five sinusoidal curves with same parameters. In the numerical simulation, the open boundary and 1:1 slope on the end of the wave tank are considered with the other conditions same as the physical experiment; the interaction between surface waves and the triangle/trapezium sandbars on the seabed is also studied. The physical experiments give the series of wave records under the interaction between surface waves and sandbars on the seabed. Based on the series of wave records, reflection coefficients are calculated by Goda's method and the Bragg resonance are obtained. Under the different wave heights, the variation of the reflection coefficient with wave-period, the resonant periods and the maximal reflection coefficients are almost the same. The numerical model based on VOF method gives the Bragg resonance phenomena and the resonant reflection coefficient agrees well with the result of physical experiment. The numerical simulation on the interaction between surface waves and the triangle/trapezium sandbars on the seabed also shows the Bragg resonance and the resonant period matches the Davies' prediction. It shows that after being improved the VOF method can be selected to further study the interaction between surface waves and sandbars on the seabed.