Calibration of a microphone phased-array for amplitude in the Virginia Tech anechoic wind tunnel

摘要

Recently, the Virginia Tech wind tunnel was upgraded to an anechoic facility. Inaddition to the reduction of the background noise in the tunnel circuit, the original hardwalledtest section was replaced by a hybrid test section that is aerodynamically closedand acoustically open. This new concept allows acoustic measurements to be carried outin the far-field and outside the flow. In this paper, a procedure to calibrate the outputlevels of a phased-array in the Virginia Tech aeroacoustic wind tunnel is presented. First,the sensitivity of the array is found by averaging the sensitivity of the all the array’smicrophones. Subsequently, corrections are first determined to account for the acousticenvironment of the test section. Finally, corrections are determined to account for theflow effects. The procedure is presented for a semi-anechoic configuration of the windtunnel.