Experimental Study On Noise Reduction Through Trailing Edge Brushes

Abstract

Within an experimental trailing edge noise reduction study in the Aeroacoustic Wind Tunnel Braunschweig (AWB) both acoustic and aerodynamic effects of trailing edge brush devices were examined. Directional microphone and hot wire measurements were undertaken on a zero-lift generic plate model (Re = 2.1 to 7.9 x 10 Million). Various brush concepts were tested to clarify the functional relationship between design parameters and the ensuing aeroacoustic properties. First results of this ongoing work indicate a significant source noise reduction in excess of 10db, thereby revealing two relevant noise reduction mechanisms. In addition to broadband turbulent boundary layer trailing edge noise also narrow band contributions due to vortex shedding from the edge were alleviated.