Hydrodynamic Coefficients of Maneuvering of a Mono-hull Planning Craft by Numerical Simulation of Restrained Test Model

In maneuvering analysis of high speed planning craft, developing the use of numerical methods, could provide a good insight into the hull maneuvering performances. In this paper, based on 4DOF system of equations for surge, sway, yaw and roll motions, the hydrodynamic coefficients related to lateral speed and drift angle are evaluated for a typical mono-hull planning craft by numerical simulations. For this purpose, the restrained test of the scaled model of the proposed craft is modeled through computational fluid dynamic by Ansys CFX and the results of simulations of its motion on straight line are extracted at two different forward speeds for different drift and roll angles. Some of these results are compared to the values obtained by available semi empirical formulas proposed by Lewandowski which showed some discrepancies. The results also show that forward speed is a main influencing factor on the hydrodynamic coefficients of maneuvering of a planning craft. Meanwhile maneuvering forces and moments tend to vary linearly with respect to lateral speed, but variation of sway force and yaw moment with respect to roll angle, tend to nonlinearity by increasing the forward speed. At lower forward speed, these relations could be well predicted by linear regressions.