尾缘多孔结构流动控制影响的数值研究

摘要

The NACA0012 airfoil with porous trailing edge(TE) is used to numerically investigate the effects on flow and aerodynamics noise at various angles of attack(AOA).It is found that at the high AOA (α≥10° before stall), the present porous TE design can reduce the noise by about 4 dB, below frequency of 1000 Hz.Comparing with the baseline airfoil, the present porous TE airfoil cause the maximum loss of lift-drag ratio is 8%, which means it can reduce noise without huge aerodynamics decay.The further flow analysis indicates the significant physical mechanisms for TE noise reduction that the pressure difference between suction and pressure surface drives air fluids permeate through porous area to generate micro-jet which breaks the separation bubble above TE.It consequently produces the attenuation of pressure fluctuation and noise reduction.%以多孔尾缘结构NACA0012翼型为研究对象,通过数值模拟手段研究了不同迎角下的流动和气动噪声影响.研究结果表明:该多孔尾缘结构在较大迎角时(α≥10°),能够降低1 000 Hz以下低频范围噪声约4 dB.相对于原基准翼型,多孔尾缘翼型的最大升阻比减少约为8%,能够降噪的同时不造成过大的气动性能改变.进一步的流场分析表明,多孔尾缘结构流动控制降低噪声的关键物理机理是:上下面压力差驱动充足气流穿过多孔区形成"微射流",对分离块进行破坏,从而衰减叶片表面的气动载荷波动,引起气动噪声降低.