Hot Thermistor Anemometer for Finite Amplitude Stability Measurements

A device similar to a hot wire anemometer has been developed in which the wire is replaced with a thermistor. Niiler has presented a theory of the response of the anemometer to velocity gradients. Experimental calibration curves are presented here to show that Niiler's model explains the operational characteristics quite satisfactorily. The associated electronic circuitry is described and the design considerations which determine the magnitudes of the various adjustable parameters are discussed. This anemometer has been used to detect the onset of the various modes of secondary flow, the amplitude of the disturbances, their wavelengths, and their drift velocities. Both velocity and temperature fields may be measured.