Experimental Determination of Frequency of Laminar-Boundary Layer Instability Noise of NACA 0012

Abstract

This paper presents simple method and new results of experimental investigation of laminar boundary-layer instability noise of an airfoil. The experimental method is based on small electret microphones, which are built in to the surface of the measured airfoil segment in pinholes. The paper discusses evaluation of the experimentally obtained data and presents new results for laminar boundary-layer vortex-shedding tonal sound frequency of NACA 0012. The main attribute of the proposed experimental method is the possibility of its usage in a non-aeroacoustic facility.