Turbulent density fluctuations in a subsonic and transonic free jet using crossed-beam schlieren techniquesScalar density fluctuations were measured nonintrusively in the shear layer of a 5.08-cm (2-in.) cold air jet using a crossed-beam schlieren method. Two statistics, covariance and three-dimensional spectrum function, were estimated for an exit Mach number range of 0.3 to 0.97. The density fluctuation intensity, integral scale, and eddy convection speed were calculated and compared to available data where possible. Spectra were found to change significantly in shape becoming less peaked between 3 and 9 jet diameters downstream from the orifice, but they consistently exhibited a -5/3 power law decay at 3, 6, and 9 diameters for frequencies above the peak.
Document ID
19790058046
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Martin, R. A. (NASA Ames Research Center Moffett Field, Calif., United States)