Numerical Simulation Of Longitudinal Motion And Added Wave Resistance Of Ship In Head Waves For Laser Radial Class

Laser Radial Class is an important type of sailing dinghy in Olympic Games.During the competition athletes will have to manoeuvre the boat in head waves,under which circumstances the dinghy will have longitudinal motions especially pitch and heave,and its added wave resistance will differ.In order to understand the basic response of the boat and help the athletes estimate how their would react when facing with head waves,and get higher speed,systematic Computational Fluid Dynamics(CFD)simulations were carried out to find the regular patterns of Laser Radial Class Dinghy sailing in head waves.The simulation results show that when sailing in calm water,the change of the resistance of naked hull follows the rule that the resistance rises as the speed of hull rises.Besides,in consideration of the longitudinal motions of the boat,as the sailing speed increases,the bottom pressure increases,the maximum zone moves towards to the stern,the splash severely around the bow,and the amplitude as well as the wave length of the stern wave and Kelvin wave get larger and larger.Meanwhile,when the speed is within the scale of 4 m/sto 6 m/s,the boat comes to a planning condition.As for the systematic regular head wave operation conditions,under the same scale of head wave,the longitudinal motions and resistance changes periodically,and when the sailing speed changes,the pattern of which are equal to that in calm water.This study discussed the change patterns of longitudinal motions and resistance of the naked Laser Radial Class Dinghy hull in calm water and systematic head waves.It provided some theoretical guidance for the athletes to understand the responses of the hull,and provided some reference for further study of the hydrodynamic performances of sailing dinghy in head waves.