Acoustic and Velocity Measurements in the Flow Past an Airfoil Trailing Edge

This thesis describes the results found during a project to investigate the sources of trailing edge noise production. A flat plate airfoil was investigated for the Office of Naval Research. This document shows the results of the two parts of this project. First an experimental database used as the input for numerical acoustic modeling at Stanford University was obtained. Therefore the flow around and inside a defined control volume was investigated using hot-wire probes (single and x-wire measurements) and pressure measurements. In the second part, far field acoustic measurements and correlation measurements between x-wire probes and the micro- phones were made to investigate possible correlation between the flow physics and the far field acoustics. The control volume boundary results show that the incoming flow is of low turbulent intensity and that the wake behind the trailing edge shows an asymmetric development. Vortex Shedding could be identified separately by acoustic and hot-wire measurements at a frequency of around 220Hz. Similar frequency behavior could be identified in the correlation measurements between the x-wire probes and the microphones.