气动噪声相似关系及在风洞试验中的应用

研究以基本气动噪声源(单极子声源、偶极子声源和四极子声源)向远场辐射声功率和物体运动过程中产生的气动噪声与运动速度、物体特征尺寸、距观测点距离和介质特性等的关系,推出了相似运动物体向远场辐射气动声的相互转换关系式,并利用气动声学风洞对高速列车模型产生的远场气动噪声进行测量,据此关系式从低风速测量结果推出了高风速结果,用试验数据进行验证.研究表明,此关系式反映了原型和模型之间在远场辐射气动噪声的相互关系,对模型试验结果分析和向原型的转换具有一定的借鉴作用.

Aerodynamic Noise Similar Relationship and Its Application to Wind Tunnel Test

Based on the sound powers of the basic aerodynamic sound sources (monopole source, dipole source and quadrupole source) radiating to the far field and their relations with the moving speed, the feature size, the distance from the observation point and the media characteristics etc, a conversion formula of the aerodynamic sound pressure level (SPL) radiating to the far field between the model and the prototype was derived. Moreover, the aerodynamic SPL outside the flow for a high speed train model was measured in an aero acoustic wind tunnel. Based on the testing results and the conversion formula, the aerodynamic SPL of the high speed train model at higher wind speed was derived from them at lower wind speeds. At the same time, the correctness of the conversion formula has been verified by the testing data. The studies above show that the conversion formula reveals the relationship of the aerodynamic noise in the far field between prototype and model and plays an important role to analyze the testing results and convert the data in the model experiment.