Test Rig Design for Unsteady Surface Pressure Measurements in Complex Flows

The paper describes the experimental setup of a wind tunnel test in the DNW's low speed wind tunnel in Braunschweig (DNW-NWB) to investigate the boundary layer in the cockpit and fuselage area for the DLR project INTONATE. In order to gain knowledge about this accelerated flow during the test, the sensors and the sensor installation play a major role. The goal of the experiment is the measurement of the turbulent boundary layer's unsteady pressure autospectra and respective cross-correlation with high spatial resolution. Therefor the sensor itself has to be small to avoid spatial averaging on the sensor surface and to allow for minimum distances between sensors in order to measure small correlation lengths. These challenges are met with a microphone MEMS array which will be fully integrated into the cockpit surface. The paper gives an overview of the model construction, the test setup and the onboard instrumentation consisting of static pressure ports, the MEMS microphone arrays and pinhole-mounted Kulites, the latter serving as reference sensors to measure the boundary layer induced pressure fluctuations.