Control and creation of tidal residual current in a semi-enclosed bay by bottom roughness with directional resistance characteristics

We have proposed a new method to activate the tidal exchange in a semi-enclosed bay by creation and control of tidal residual current. In this new method, the tidal current is produced and controlled by unsymmetric bottom structures, which change characteristics of resistance according to flow direction. In this study, the tidal current and particle-tracking simulations for various arrangements of bottom roughness in a semi-enclosed model bay were carried out. As a result of numerical experiments, it becomes clear that it is possible to control the tidal residual current and to activate the tidal exchange by only operation of bottom roughness.