风-浪-舰耦合对舰船尾流场及直升机气动的影响

Effects of wind-wave-ship coupling on ship airwake and helicopter aerodynamics

为研究波浪和舰船运动对高海况下舰载直升机起降的影响,建立了一套耦合风-浪-舰和直升机的多相流数值模拟方法。使用动态流体作用模拟舰船运动,采用动量源方法模拟直升机旋翼,对3~6级海况下ONRT舰船摇荡运动时的尾流场非定常气动特性进行了研究,并计算了UH-60A直升机旋翼气动载荷的时间历程。研究表明:6级海况下流场速度分量和旋翼气动载荷的波动达到5级海况的2倍,而3~5级海况之间的差别较小;悬停跟进时直升机不断出没于舰船运动导致的尾流中速度和涡量不同的区域,使得旋翼气动载荷有极强的非定常特性;在6级海况下,旋翼拉力与波浪-舰船耦合运动同周期的波动达到20%,并伴随着穿越尾流剪切层时产生的5~10 Hz的小扰动。

To research on the effects of waves and ship motions on shipborne helicopter,a numerical simulation method of multiphase flow coupled by the wind,wave,ship and helicopter was developed.The ship motions were simulated by the dynamic fluid interaction module,and the helicopter rotor was simulated by the momentum source approach.The unsteady aerodynamic characteristics of the ONRT ship airwake while pitching and heaving at sea state 3~6 were studied,and the time history of the UH-60A helicopter rotor thrust and pitch moment was calculated.It is shown that the fluctuations of velocity components and rotor airloads of sea state 6 are up to 2 times that of the sea state 5,while there are less differences among sea state 3~5.The rotor airloads present strong unsteady characteristics when the hovering rotor constantly crosses over areas with different velocities and vorticities.At sea state 6,there are 20%rotor thrust fluctuations with the same period as ship motions and 5~10 Hz perturbations due to the swinging separated shear layer.