Measurments of steady flow velocity using the termal wave method

Author: J. Kiełbasa

The paper provides 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 assumed that source power is sufficiently smali so that the produced temperature increase of the flowing medium will not change its physical properties.

The solution to the heat conduction equation with a periodic source might be expressed in a form of a simple product, yielding the thermal wave amplitude and phase.

The flow velocity formula can be derived from phase distribution in the function of distance from the source.

The thermal wave method might be easily applied in calibration of thermoanemometric sensors for low-speed measurements.