机动飞行下飞行器表面噪声预计

Prediction of aircraft surface noise during maneuvering flight

针对飞行器高机动大过载飞行时表面噪声预计问题开展研究.对基于分区混合与流尺度混合的双重RANS/LES混合模型进行修正,对复杂分离流动进行精确模拟.建立一种同时计算气动/运动、内/外流、可压缩/不可压缩流的计算方法,利用双重RANS/LES混合模型结合六自由度运动方程模拟飞行器机动过程并计算飞行器表面声载荷。计算结果表明进气道及尾喷口处声载荷较大,正过载飞行时由于飞行速度较大、尾喷口喷流噪声影响使得表面噪声大于负过载.喷流噪声对机身总声压级贡献率由前到后逐渐增大.机动状态下,飞行器表面涡流运动增强,压强脉动大于巡航状态,使得相同飞行速度下机动状态表面总声压级大于巡航状态.

Research is carried out on the prediction of aircraft surface noise during flight with high maneuverability and high overload.The dual hybrid Reynolds-averaged Navier-Stokes/large eddy simulation(RANS/LES)calculation model based on zonal mixing and turbulent scale mixing is modified,and the new hybrid model is established to simulate complex separated flow accurately.A calculation method for simultaneously calculating aerodynamic/motion,internal/external flow,and compressible/incompressible flow is employed.The dual hybrid RANS/LES model combined with six-degree-of-freedom motion equations is used to simulate the maneuvering process of the aircraft and calculate the surface acoustic load.The calculation results reveal that the acoustic load at the inlet of the engine and tail nozzle is large.During positive overload flight,the surface noise is greater than negative overload due to the stronger turbulent fluctuation on the aircraft surface and the impact of jet noise at the tail nozzle.The contribution rate of jet noise to the overall sound pressure level(OASPL)of the fuselage gradually increased from front to rear.In the maneuvering state,the vortex motion on the aircraft surface is enhanced,and the pressure fluctuation is stronger than that in the cruise state,which makes the surface acoustic load greater than that in the cruise state.