A High-Speed PIV Study on trailing-edge noise sources

Abstract

Airframe noise is essentially due to the interaction of unsteady, mostly turbulent flow with the structure of the airplane, particularly caused by vortical flows around edges or over open cavities. A classical problem in this field is the trailing edge noise, which involves different noise generating mechanisms. The major noise contribution is provided by the span-wise component of vorticity, the corresponding dipole (“principal edge noise dipole”) is the sc. perturbed Lamb vector being perpendicular to the plane of the plate. A numerical simulation of trailing edge noise has been performed, based on HS-PIV input data. The source term of the acoustic analogies was directly computed from the measured HS-PIV velocity field quantities (namely the instantaneous velocity, vorticity and the mean flow). After linear interpolation onto the body-fitted block-structured grid for the trailing edge, these source term values were fed into the subsequent computational aeroacoustic (CAA) simulations.