Unsteady ship-bank interaction: a comparison between experimental and computational predictions

A collaborative exercise is presented where different numerical methods were used to recreate the forces acting on a ship model while executing captive model tests along a channel which has an unsteady cross section (dock opening). Such a layout is typical for a harbour environment. The unsteady nature of the cross section leads to peak values in forces, sinkage and free surface deformations. Experimental tests were conducted by Flanders Hydraulics (with the co-operation of Ghent University). Numerical contributions involve three potential flow methods (Strathclyde University and Pinkster Marine Hydrodynamics) and one RANS method (Federal Waterways Engineering and Research Institute of Germany). All methods are capable of qualitatively predicting the water level variations and sinkage and trim of the vessel. RANS has a better capability of predicting the unsteady sway force and yaw moment acting on the ship including sinkage and trim, but it comes at a much higher computational cost.