On the modeling of passing ship effects

This paper presents a method to compute the effect of passing ships on moored ships. The method is in principle based on the method originally developed by Pinkster. He developed a method to quantify these effects based on linear potential flow. The disturbance of the passing vessel on the port geometry and moored ship is analyzed using a double-body flow. The reflection of this disturbance on the geometry of port and moored ship is analyzed using a linear diffraction method. This method has shown to give good results for ships sailing straight ahead, but is expected to be less accurate for passing ships sailing under a drift angle, in which case the viscous wake related to the lift force on the vessel becomes more dominant.
Therefore, the method by Pinkster is extended with viscous effects. The disturbance caused by the passing ship on the moored ship and port geometry is computed by a RANS method instead of a potential flow method. The diffraction effects due to the presence of the moored ship and port geometry is accounted for in the same way as Pinkster did by means of a linear diffraction analysis. A comparison is made with model tests for a ship passing a moored ship along a quay at various drift angles. Results are shown for the traditional method (potential flow disturbance) and for the considerably improved method (RANS disturbance).