A method for partitioning the sources of aerodynamic loading noise in vortex dominated flows

Abstract

Aerodynamic loading noise is the primary noise component in a wide range of applications. While it is well known that the loading noise is generated by the time-varying aerodynamic forces on the surface, further segregation of the loading noise into the components related to the flow structures and fluid dynamic mechanisms would be useful in pinpointing the source mechanisms for this noise. In the present study, an aeroacoustic partitioning method which can decompose the loading noise into the components associated with their generation mechanism as well as specific vortex structures is proposed. The method combines a previously developed force partitioning method with acoustic analogy-based sound prediction. The method is applied to the canonical dipole sound generation by a circular cylinder as well as the loading noise generation by a pitching airfoil. The results demonstrate the ability of the method to identify the dominant loading noise generation mechanisms and enable quantification of the effect of the vortex structures around the body on the generation of the loading noise.