Effect of the Earth Rotation on Tide Induced Sediment Transport

Semi-enclosed seas are generally composed of narrow straits and wide basins, forming a strait-basin system. In the strait-basin system where tidal current prevails, the strong tidal current (tidal-jet) flowing into the stagnant basin from the strait produces a vortex-pair: a pair of counter-rotating vortices. The clockwise and anti-clockwise vortices are transported from the strait to the basin every tidal period. These vortices accompany strong convergence in the bottom layer and carry the suspended matter at the first stage. In the case of the clockwise vortex, a low pressure feature at the first stage changes into a high pressure one in the damping process, while the anti-clockwise vortex damps without changing its characteristics. Due to the above transformation of the clockwise vortex, the divergence in the bottom layer replaces the convergence. The difference of the damping process between the clockwise and anti-clockwise vortices, combined with the transport processes of these vortices, seems to play an important role in the sediment transport.