Hot-wire measurements in compressible flows

Conditions for hot-wire fluctuation measurements at high velocities are considered. Particular attention is given to the determination of sensitivity coefficients, the conditions for the application of constant-resistance and constant-current anemometers, and measurements at supersonic velocities. It is concluded that high-velocity measurements will be successful only if the following conditions are met: the availability of proper equipment, the development of the probe calibration method, and the substantiated interpretation of the measurement results. The method used at supersonic velocities not only can but must be used at high subsonic velocities