Measurements of Scalar Power Spectra in High Schmidt Number Turbulent Jets

Single-point, jet-fluid concentration measurements obtained from high Schmidt number Sc -- 1.9 x 10 to the 3rd power turbulent jets permit an investigation of temporal scalar power spectra, for et Reynolds numbers in the range of 1.25 less than or equal to Re x 10-4 less than or equal to 7.2. At intermediate scales, we find a spectrum with a logarithmic derivative slope that is increasing with Reynolds number, in absolute value, but less than 53 at the highest Reynolds number in our experiments. At the smallest scales, our spectra exhibit no 1-k power-law behavior, possessing a log-normal region over a range of scales exceeding a factor of 40, in some cases.