Steady state velocity measurements by the thermal wave method

Author: J. Kiełbasa

Potential applications of thermal waves to airfl ow velocity measurements were investigated experimentally.

The experimental procedure utilises a theoretical description of thermal waves generated in a steady state stream of a medium, by a linear source whose power varies sinusoidally in time. It is assumedthat source strength is suffi ciently small so that the produced temperature increase of the fl owing mediumwill not change its physical properties. Besides, an assumption is made that the velocity fi eld will not bedisturbed by a hot wire (8 μm in diameter).