基于混合CFD方法的旋翼桨-涡干扰噪声计算

建立了一个基于Euler方程和自由尾迹分析的新的、高效的混合计算方法,用于旋翼桨-涡干扰(BVI)气动和噪声特性的研究.在该方法中,仅针对单片桨叶进行计算,通过求解Euler方程来捕捉流场中旋翼近尾迹的影响以及桨叶表面的非定常载荷,流场空间中旋翼远尾迹的位置由自由尾迹模型给出;提出了广义网格速度方法以将旋翼远尾迹的影响...

Rotor Blade-vortex Interaction Noise Prediction Based upon Hybrid CFD

A new hybrid method based on Euler equation and free wake analysis is developed for studying the aerodynamic and acoustic characteristics of rotor blade-vortex interaction (BVI). In this method, the flowfield of just one blade is solved. An Euler solver is used to capture the effect of near wake and unsteady loading on the blade surface; a free wake model is employed to account for the effect of the far wake. To simplify computation, an effective approach called the generalized grid-velocity approach is presented. The acoustic prediction is based on the well-known FW-H equation. By this method, the aerodynamic loading and acoustic calculations are performed for an AH-1/OLS rotor in the BVI condition. A comparison with available experimental data has validated the present method. Also, the computation results indicate that, the BVI phenomena will occur at several azimuthal angles on the rotor in the descent flight condition, and that BVI loading is mainly caused by the high rate of change of pressure within 10% of the leading edge. The typical BVI noise is impulsive and has strong directivity.