音響インテンシティ法によるジェットスクリーチの音源探査

抄録

We theoretically and experimentally investigated the relation between sound source and sound intensity field taking real effects into consideration. Our purpose is to obtain the accuracy of the sound intensity technique when applied to aerodynamic acoustics noise such as jet screech. Shock-vortex interaction model was used to predict the sound intensity field. It was tested and compared with experimental measurements. Experimental results showed that the resultant vectors of sound intensity almost focus on a point corresponding to the location of the shock cell. However, the location sometimes deviated from the jet flow field. Furthermore, it was difficult to locate the source of a strong spectrum component. The deviation was considered to be caused by the spread of the source region and the fluctuation of the strong spectrum component was considered to be caused by unsteadiness of jet screech. We clarified the local deviation by the calculation of far field sound intensity using near field sound intensity and the directivity of distributed screech sources.