Novel non-intrusive measurements are presented to lend insight into behavior of 4 th order velocity fluctuation spectral statistics and space-time correlations in the developing shear layer of hot supersonic jets. Fourth-order statistics are dominated by the chaotic motion of large-scale coherent structures, which appear largely as the 'skirts' of probity density. Due to the interest in predicting the power spectral spectral density of acoustic density fluctuations, a mean-square quantity, 4 th order statistics hold direct application in acoustic analogies. Despite this, limited data exist for fourth-order spectral correlations of velocity, particularly in hot supersonic jets. A Doppler-based measurement technique with a frequency resolution of 125kHz is employed to obtain time-resolved measurements and used to determine 2 nd and 4 th order space-time correlations, integral timescales, convection velocities and auto-spectra on the lip line of a hot (TTR=1.6 and TTR=2) supersonic perfectly expanded jet at M d =1.65. Comparator data obtained in the same facility using laser Doppler velocimetry is analyzed with respect to 4 th order terms indicating the importance of the 4 th order correlation in the region of immediate interface between the potential core and the shear layer.
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