椭球体水动力及流场的数值模拟和试验研究

Numerical simulation and experimental study on hydrodynamics and flow field of ellipsoid

采用数值模拟及试验测试两种手段对椭球体直航及斜航的水动力、表面压力及流场特性进行研究,探讨了速度和漂角对椭球体所受力及扭矩的影响,以及在这些因素影响下表面压力的变化规律.通过PIV(粒子图像测速)测试系统获取椭球体不同漂角时的速度场,与数值方法对比展示了椭球体在不同漂角下的流动分离现象.结果表明:直航条件下,椭球体阻力随速度增加而增加,轴向压力艏艉部高中部低,流动分离现象不明显;斜航条件下,随着漂角的增大,阻力减小,侧向力和转艏力矩增大,迎流面及背流面压力增大,涡量增大且流动分离点前移.研究结果可为潜艇等的操纵性预报提供指导.

The hydrodynamic,surface pressure and flow field characteristics of the ellipsoid in direct and oblique navigation were studied by numerical simulation and experimental test.The effects of velocity and drift angle on the force and torque of the ellipsoid and the variation of surface pressure under these factors were discussed.Finally,the velocity field of the ellipsoid at different drift angles was obtained by PIV(particle image velocimetry)test system.Compared with the numerical method,the flow separation phenomenon of the ellipsoid at different drift angles was demonstrated.The results showed that under direct navigation,the ellipsoid resistance increases with the increase of velocity,the axial pressure is high at the bow and stern,and low at the middle,and the flow separation is not obvious.Under oblique navigation conditions,with the increase of drift angle,the resistance decreases,the lateral force and yaw moment increase,the pressure on the upstream and downstream surfaces increases,the vorticity increases and the flow separation point moves forward.The results provide a reference for the maneuverability prediction of submarines and other underwater vehicles.