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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耦合到流场的求解中;噪声的分析采用基于声学类比法的FW-H方程。应用上述方法对AH-1/OLS旋翼BVI状态的气动载荷和噪声进行了计算,并与可得到的试验数据对比,验证了方法的有效性。计算结果表明:下降飞行状态的旋翼,在桨盘面会产生多处BVI现象,而干扰脉冲载荷主要来自桨叶前缘10%弦长内的压强突变;典型的BVI噪声具有多个正、负脉冲声压,且具有较强的方向性。
A new and efficient hybrid calculation method based on Euler equation and free wake analysis is established for the study of aerodynamic and noise characteristics of rotor blade propeller-vortex disturbance (BVI). In this method, the calculation of the blade is performed only by solving the Euler equation to capture the effect of the wake near the wake in the flow field and the unsteady load on the blade surface. The position of the rotor’s wake in the flow field space is determined by the free-wake model The generalized grid velocity method is proposed to couple the influence of the rotor’s wake to the solution of the flow field. The noise analysis uses the FW-H equation based on acoustic analogy. The aerodynamic loads and noise of AH-1 / OLS rotors in BVI state are calculated by the above method and compared with the available experimental data to verify the effectiveness of the method. The calculation results show that the rotor flying in the down flight state will have many BVI phenomena on the propeller disk surface, while the disturbance pulse load mainly comes from the sudden change of pressure in the 10% chord of the blade leading edge. The typical BVI noise has multiple positive and negative pulses Sound pressure, and has a strong direction.