Comparison of Microphone Array Measurements of an Airfoil with High-Lift Devices in Open and Closed Wind Tunnels

Kurzfassung

A comparison between microphone array measurements in closed and open test sections of wind tunnels is presented using a generic 3-element high-lift system. The aeroacoustic measurements were simultaneously performed with aerodynamic measurements with the goal of examining the test section-dependent aeroacoustic and aerodynamic characteristics and their influences on aeroacoustic sound generation and propagation. The study focuses on the beamforming results in both wind tunnel types with respect to source position, relative and absolute levels of beamforming results and integrated spectra by considering the aerodynamic performance in terms of the lift coefficient and static pressure distribution along the model. In both wind tunnels the same phased microphone array is used for the measurements, whereby the aim is to keep the experimental setup and conditions as identical as possible in both cases in order to be able to examine the test section-dependent effects.