理论和数值方法预报的船舶姿态改变对螺旋桨非定常轴承力的影响

Influence of ship attitude change predicted by theoretical and numerical methods on propeller's unsteady bearing force

对船舶两种不同姿态下的螺旋桨非定常轴承力进行预报,并对其谐调分量进行研究.在此基础上,研究船舶姿态改变对螺旋桨非定常轴承力的影响.结果表明:船舶姿态改变(纵倾和吃水增加)时,桨盘面伴流分布的低阶分量的幅值均相应增加,从而使螺旋桨三向轴承力的谐调分量的幅值均有不同程度的增加,其中,横向力幅值的增加明显.此外,研究证明:拟定常方法可以较准确地预报船舶不同姿态下螺旋桨的非定常激振力以及姿态改变造成的螺旋桨激振力的变化;将船和桨分开模拟的方法也可以准确地预报船舶不同姿态下螺旋桨的非定常激振力.

The unsteady bearing force of propeller under two different positions was predicted and its harmonic component was studied.Based on this,the influence of ship attitude change on unsteady propeller bearing forces was studied.Results show that when the ship attitude changes（trim and draft increase）,the amplitudes of low harmonics of the wake at the propeller plane increase,which makes the amplitudes of three-dimension bearing forces increase to some extent.Among them,the transvers force increase obviously.In addition,the results prove that the quasi-steady method is capable of predicting unsteady propeller bearing force of the ship with different attitude and also the amplitude change of propeller bearing force caused by ship attitude change.The method of simulating the ship and the propeller separately can also accurately predict propeller bearing forces of the ship with different attitudes.