An Improved Correction Method for Sound Source Drift in A Jet Flow and Its Application to A Wind Tunnel Measurement

摘要

The change of sound propagation characteristics during sound propagation in jet flow in an open-jet wind tunnel makes the sound information distorted, which is obtained from outside of the jet flow. This paper focuses on the variation of sound propagation direction, which is one of main features for the change of sound propagation. On the basis of the average flow pattern in the shear layer of jet flow which is obtained by CFD method, the simplified shear layer flow model is put forward. By combining the flow model with the geometrical acoustics theory, an improved correction method is presented to estimate the drift of sound source position of a point source in the core area caused by sound propagation in jet flow. Furthermore, the sound source drifts due to variation of sound propagation direction in jet flow of an aero-acoustic wind tunnel were calculated by CFD method. At the mean time they were tested in the same aero-acoustic wind tunnel. Compared to results from the test and Amiet's method, more precise calculation results regarding sound source drift at different sound source positions along the jet flow direction can be obtained via the improved correction method in this paper. The improved correction method can be applied not only to correct the results measured from the outside of jet flow in a wind tunnel test, but also to analyze the sound propagation process in the jet flow.