Measurement of Broadband Noise Generation on Rod-Airfoil-Configurations

The subject of this paper is the investigation of flow induced broadband noise generated due to unsteady loading of an airfoil. This is done in an experimental way based on acoustic measurements made on a rod-airfoil-configuration. The configuration is varied by changing the diameter of the rod and adjusting different gaps between the rod and the airfoil leading edge. Additionally, two types of airfoils are used sucessively. In total, 75 configurations are tested. All measurements are conducted in the aeroacoustic wind tunnel of the Brandenburg University of Technology at Cottbus for flow speeds between 26 m/s and 72 m/s. A 38 channel microphone array is used to record the acoustic data. The data are then processed using DAMAS, a complex beamforming algorithm. Both leading edge noise and trailing edge noise are analyzed. The results show that the noise generation on the rod-airfoil-configuration for lower frequencies depends more strongly on the varied cylinder diameters than on the width of the gap.