Mixture fraction field in a turbulent nonreacting propane jet

Time- and space-resolved mixture fraction measurements have been made throu ghout a turbulent nonreacting propane jet issuing into coflowing air using laser Rayleigh scattering, The objective of the measurements has been to ob tain a better understanding of the Row structure and mixing process in turb ulent variable-density jets where turbulent mixing has been decoupled from the effects of chemical heat release found in highly exothermic reacting je ts. The measurements yield probability density distributions of the mixture fraction, from which the means, higher moments, and intermittency are calc ulated, Time histories of the Rayleigh signal are analyzed to obtain the po wer spectra and autocorrelations, Comparisons are made with results for oth er constant- and variable-density turbulent jets, and the observed differen ces are discussed.