CFD-based predictions of hydrodynamic forces in ship-tug boat interactions

Abstract

ABSTRACTThis paper presents numerical investigations on the ship-ship interaction between a large oil tanker and a tug boat by means of Reynolds Averaged Navier-Stokes method. Prior to the systematic simulations for predicting the hydrodynamic interactions between the ships, a grid convergence study is performed to estimate the numerical error and uncertainty in ship resistance predictions. The grid convergence results indicate that the numerical error caused by the grid discretization is small, from which an appropriate grid density is selected for the systematic investigations. In the systematic computations, the ship-tug boat interaction forces are predicted in terms of the effects from several aspects: relative positions between the two ships and drift angle of the tug boat. In comparison with previous studies on the interaction effects between two large ships with comparable sizes, the forces acting on the tug boat are more considerably influenced by the ship-tug boat interaction effects since the scale of the tug boat is much smaller than the large ship. The predicted pressure distributions further verify this phenomenon. From the systematic computations, it is suggested that in practical operations the effects on the hydrodynamic performance of the tug boat resulted from the ship-tug boat interaction should be carefully taken into account.