Measuring the velocity and temperature wake

Author: J. Kiełbasa

The paper presents the results of the research on the velocity and temperature wake produced behind the hot wire several micrometers in diameter, during the flow of a medium.

The wakes were measured using a single-wire probe operating in a modified constant-temperature system enabling sine modulation of the overheating ratio.

That provides for temperature compensation of the anemometer readouts.

The mean value of the overheating ratio N and the amplitude of its modulations n being preset, the voltage across the hot wire is then developed into the Fourier series.

Thus the constant component Uo and the first harmonic component u1 can be obtained.

These two being known, one can get the information about the flow velocity v(x, y) and the temperature of the medium T(x, y) at a measurement point (x, y).

Thus obtained results are presented in diagrams, in the standardised form. It can be seen that both the velocity and temperature distributions yield the Gaussian curve pattern.