飞机螺桨声场的数值模拟方法

NUMERICAL PREDICTION OF SOUND FIELD GENERATED BY PROPELLER

本文给出了预测飞机螺桨在自由空间内幅射的气动声场的一种数值方法。即时域内进行延迟时间积分的一类方法。在该方法中使用片条假设 ,并考虑厚度声源和负荷声源项作为非紧致声源。计算与实验结果对比表明 ,该方法和相应软件可作为一种工程手段来使用。

A fast and accurate numerical method is presented for predicting the sound field generated by subsonic propellers.The free space field,including the near and far sound field radiated by noncompact sources,is calculated by means of a retarded time integration in time domain.The FW H equation is applied to solving the sound field generated by moving boundaries of solid body in the flow field,but its quadrupole term is neglected,thus the noncompact sources mean the thickness source and the load source both included in the dipole term.According to the assumption,the sound field generated by a 3 D shaped propeller is considered as the sum of the terms radiated by each strip element located spanwise.The pressure chordwise distribution at each element should be known before solving the sound field.For this purpose a code solving 2 D compressible full velocity potential equation with body fitting coordinates is used which has been developed by BUAA previously.Comparison of calculated results with test data proves the present method and the code to be useful engineering tools.This conclusion has been also testified in the design of a propeller.