The density field of cylindrical supersonic jets is investigated by Mach-Zehnder interferometry. The optical phase shift is extracted from the interferograms by digital image processing. Disturbing turbulence effects in the free shear layer are eliminated by sequential averaging of the phase shifts of several experimental images. The resulting steady state phase shift is used to calculate time-averaged interferograms and to reconstruct the density field by computerized tomography. The obtained results are compared with theoretical predictions and good quantitative agreement is found.
Experiments in Fluids
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