Identification of Dominant Acoustic Sources in Flows around Square Cylinder in a Uniform Flow

Abstract

To identify dominant acoustic sources in flows around a two-dimensional square cylinder in a uniform flow for the freestream Mach number from 0.2 to 0.6, the contributions of each term in acoustic sources in the Curle’s and Lighthill’s equations on the acoustic field are investigated. The acoustic fields are predicted by the direct simulations, and are decomposed into those based on each acoustic source. The results show that the contributions of the sound by the quadrupoles in the Curle’s equations are not negligible for M 0.4. It is also clarified that the momentum term of the Lighthill’s acoustic source is the dominant acoustic source for all the Mach numbers.