摘要
This study is dedicated to numerically investigate the dynamic behavior of a missile released from a helicopter under the influence of downwash from the rotating rotors using AGM-114 Hellfire and UH-60 as the testcase.Simulations are conducted using unsteady Reynolds-averaged Navier-Stokes(URANS)with shear stress transport(SST)k-ωturbulence model,incorporating six-degree-of-freedom(6-DOF)motion and overset grid.Two releasing scenarios,viz.,hover and forward flight,are analyzed under varying missile launch thrust and helicopter forward flight speed.Results reveal that the rotor downwash significantly affects the stability of the missile,particularly during hovering case,where low thrust prolongs wake interaction.In forward flight,the increased airspeed can in principle reduce wake influence but introduces asymmetrical aerodynamic effects on the trajectory of the missile.The findings offer guidance for missile release and launch planning in rotorcraft operations.
直升机机载武器发射投放过程的姿态和轨迹与高速旋转主旋翼强烈下洗流存在较为强烈的动态耦合特性,从而影响武器投放的安全性和精准性。本文以UH⁃60通用直升机和AGM⁃114地狱火导弹为对象,利用高精度数值仿真方法研究直升机下洗流影响下的武器投放特性。数值方法采用非定常雷诺平均Navier⁃Stokes(Un⁃steady Reynolds⁃averaged Navier⁃Stokes,URANS)结合6自由度(Six⁃degree⁃of⁃freedom,6⁃DOF)的气动⁃运动耦合仿真方法,结合嵌套网格技术对直升机悬停和前飞情况下武器投放全过程开展动态仿真。数值仿真结果表明,在悬停状态下,武器投放的稳定性受到直升机主翼下洗流的影响较为明显;随着前飞速度的增加,下洗流和导弹运动特性的耦合影响降低,但会带来轴向不对称的特性从而影响导弹的横航向轨迹。研究结果可为直升机机载武器的投放策略提供参考。
基金
supported by the National Natural Science Foundation of China(No.11602200)。
