风洞中未知声源漂移误差的逼近修正

Drift error correction of unknown sound source in wind tunnel using approximation method

风洞试验中外场声源定位因射流结构产生声源漂移,未知声源因位置不确定造成的定位焦距不准确将增大测量声漂移误差。本文基于几何声学理论推导,确定声漂移量误差与定位焦距误差成正比关系,基于此关系,针对固体表面目标声源空间分布情况,通过试验件外形几何关系建立声源位置函数,用逼近法获取更精准的定位焦距进而降低声漂移误差,其结果通过风洞试验验证。研究表明,此逼近法能快速降低定位焦距误差,消除由位置不确定带来的声漂移量误差。

In wind tunnel test,sound source drifts due to jet structure when locating in outfield. The measured sound drift error is enlarged due to inaccurate locating focus distance caused by uncertainty of sound source location. Base on geometric acoustics theory,this paper proofs that the acoustic drift error is proportional to the locating focus distance error. The position function of sound source is established using the surface geometric relationship of test piece according to the spatial distribution of the target sound source. More accurate locating focus distance is obtained by approximation method,thus,the sound drift error was reduced. The effectiveness of the method is verified by wind tunnel test. This approximation method can reduce the locating focus distance error apace and eliminate the sound drift error caused by location uncertainty.