David Stewart Weaver
Professor Emeritus, Mechanical Engineering

My current research interests are primarily in the area of flowinduced vibrations. Whenever a structure is exposed to a flowing fluid, it will respond to turbulent pressure fluctuations or periodicity in the flow. In certain cases the structure may interact with the flow in such a way that it becomes unstable. To ensure structural integrity, the vibration amplitudes must be kept within acceptable limits and instability must always be avoided.

The goal of my research is to develop an understanding of the fluid excitation mechanisms and, ultimately, to be able to design structures against destructive flow induced vibrations. As many of these problems involve high Reynolds number separated fluid flows, it is often necessary to study the phenomena experimentally. To this end, wind and water tunnel facilities have been developed and the fluid behaviour is studied using hot wire and laser doppler anemometry as well as flow visualization. Theoretical models are also developed whenever possible using both analytical and numerical techniques.

Current applications of this research at McMaster include heat exchanger tube arrays (especially nuclear steam generators), hydraulic gates and valves, bellows expansion joints and acoustic excitation in pipelines. Research has also been conducted on the active control of flow induced vibrations and acoustic resonance using acoustic feedback techniques. All of this research has been motivated by practical problems and is supported through industrial contracts as well as research grants.