Simultaneous Measurement of Concentration and Velocity by Applying Hot-Wire Techniques. 3rd Report. Statistical Investigation Aided by a Microcomputer.

Abstract

In the turbulent mixing regions which were formed by issuing gases of different densities into ambient air, the instantaneous values of concentration and velocity are derived by a set of probes consisting of an ordinary hot-wire and a probe for concentration measurement. The signals of the two probes are input into a microcomputer, and the calculations are carried out immediately. The instantaneous measuremests of concentration and velocity make possible statistical investigation into the turbulent mixing region. The present paper provides some illustrated instances on the power spectra. The integral length scales for concentration and velocity are estimated by the autocorrelation coefficients which are obtained by the instantaneous values. The comparison between the scales for concentration and velocity shows that the length scale for concentration is much larger than that for velocity. The accuracy of this method of measurement is discussed.