三维FW-H方程与CAA数值模拟匹配技术研究

本文研究了三维FW-H方程与CAA数值模拟匹配技术。首先验证了适于亚音任意运动声源的Farassat时域公式和适于亚音匀速直线运动声源的Lockard频域公式,采用均匀流中单极子源声辐射问题对两类公式进行了校核。进一步,采用FW-H／CAA匹配技术对风扇／压气机前传声进行了预测。近声场基于轴对称三维CAA方法获得,远声场则基于近声场数据采用三维可穿透FW-H方程时域公式进行预测,并校核算例着重分析了不同积分面对远场声指向性的影响。本文研究证实了FW-H／CAA数值模拟匹配技术的可行性和解决工程实际问题的潜力。

ON THE MATCHING TECHNOLOGY BETWEEN THE 3-D FW-H EQUATION AND CAA NUMERICAL SIMULATIONS

This paper investigates the matching technology between the 3-D FW-H equation and a Computational Aeroacoustics (CAA) approach. The time-domain formula suitable for subsonic arbitrary moving sound sources due to Farassat and the frequency-domain formula valid for subsonic rectilinear moving sound sources by Lockard are validated by the case of the sound radiation from a monopole in uniform mean flows Furthermore, the FW-H/CAA matching technique is applied to predict the forward sound propagation from a fan/compressor. The near sound field is calculated by an axisymmetric 3D CAA approach. The far sound field is computed based on a penetrable FW-H time-domain integration method with the near sound field data as input. Much attention has been paid to the influence of the integration surface on far field directivities. This investigation demonstrates the feasibility and potential of the FW-H/CAA matching technology on solving real engineering problems.