An experimental study of flow induced vibration on a tensioned membrane

Abstract

In pursuing noise and wave control with minimal aerodynamic or hydrodynamic sacrifice, a tensioned membrane is used to line the otherwise rigid duct wall. The membrane vibrates in response to the grazing incident waves and the vibration serves to reflect the wave towards its source. The mechanism is identical to what happens in a rig of active wave control, but the difference is that the current rig has no active component. For the purpose of wave control, the device has been tested successfully without flow and with moderate flow conditions commonly found in air ventilation systems. When the flow speed is further increased, flow induced vibration occurs. This study reports the phenomena of such vibration under various flow speeds and membrane tensions. Transient process of exponential vibration growth is recorded and analysed together with the boundary layer measurements. The effects of an external cavity as well as the lateral membrane tension are also found to be significant. Other possible mechanisms for the flow induced vibration are also explored and discussed.