Study of Passing Ship Effects along a Bank by Delft3D-FLOW and XBeach

Abstract

When a ship sails with a certain speed, there is always a return current along and under the ship. The return current induces a water level depression around the ship. When the ship travels along a bank, the flow field around the ship is asymmetrical. Additional bank effects will be induced. A reliable estimation of all these effects and the resulting behaviour of the passing ship moving along the bank is of great importance to ensure the safe passage of the ship through the restricted waters. The paper presents results of numerical predictions with the open source software Delft3D-FLOW and XBeach of the effects of a ship travelling along a bank. Both models solve the depth averaged non-linear shallow water (NLSW) equations. By applying a moving pressure field method, simulations are carried out for a ship travelling along a sloping bank with a certain speed. Water level fluctuations of the free surface and the depth averaged flow velocities are obtained. The water level fluctuations at three different wave gauges are compared with data from measurements in a physical model. Based on all computations, conclusions are presented about using the moving pressure field method to simulate the passing ship effects sailing along a bank.