Removing unwanted signals from wall pressure and vibration measurements on a structure subjected to turbulent boundary layer excitation.

Abstract

Fluid‐structure interaction experiments typically involve measurements of the excitation force (or pressure) and the corresponding vibration response to the excitation. In addition to desired flow information, measured turbulent boundary layer wall pressure data often include unwanted signals such as acoustic pressures and vibration induced pressures. Measured vibration data on a structure can also include unwanted electrical noise and vibration energy from adjacent structures. A noise removal technique is presented, which allows one to remove an unlimited number of unwanted correlated signals from a set of measured data. In its simplest form, this technique is related to the coherent output power. However, the more general technique provides an ability to remove multiple signals and to retain complex values (magnitude and phase). These advantages can yield significantly greater information of the flow field and structure under investigation. This technique is demonstrated using measurements from an aluminum cylinder internally filled with water flowing at 20 ft/s.