Experimental study of flow structures of a solitary wave propagating over a submerged thin plate in different angles using PIV technique

Abstract

This research presents an experimental investigation into the interaction of a solitary wave and a submerged thin plate under different angles. Experiments are conducted to measure both velocity and vorticity by using the Particle Image Velocimetry (PIV) technique. Effects of changing the thin plate angle on the wave height and wave speed are analyzed through the use of wave height gages. Vortices are generated when the solitary wave is transmitted over the obstacle. Understanding the formation and location of the vortices will help analyze the obstacle effect on the flow. In the initial stage, a thin plate is located vertically, and flow structures are visualized. The plate is then deviated from the vertical direction towards positive angles (the direction of wave propagation) and towards negative angles in the opposite direction. In order to study the effects of the plate angle on the flow structures, experiments are carried out for three positive and three negative angles. Comparison of the formed vortices at different angles shows the formation of an additional vortex near the bottom of the channel for positive angles, as opposed to negative angles. The larger the angle is, the less the formation time of the vortex at the bottom of the channel will be. The study of the clockwise vortices formed behind the obstacle shows that increasing the plate angle in both directions decreases their strength. The clockwise vortices of negative angles are stronger than those of positive angles. In addition, changing the plate angle to the negative direction causes more wave height and wave speed reduction than changing it to the positive direction.