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Investigation of the generation of nonlinear waves by a temporal supersonic round jet
1 : Laboratoire de Mecanique des Fluides et d'Acoustique
(LMFA)
-
Site web
CNRS : UMR5509, Université Claude Bernard - Lyon I (UCBL), Ecole Centrale de Lyon, Institut National des Sciences Appliquées [INSA] - Lyon
36 Av Guy de Collongue 69134 ECULLY CEDEX -
France
A temporally-developing supersonic round jet at a Mach number of 2 and at a diameter-based Reynolds
number of 3125 is computed by Direct Numerical Simulation in order to investigate sound generation me-
chanisms in supersonic axisymmetric sheared flows. It is found that as the potential core closes, strong,
steep pressure waves are radiated. At the same time, high turbulence levels and supersonic convection
velocities are found inside the jet. Positive levels of skewness of the pressure fluctuations and of its time
derivative are observed in the radiated sound field. This is similar to measurements made in the pressure
fields of supersonic jets exhibiting crackle noise.
