Compressibility effects in a turbulent annular mixing layer. I: Turbulence and growth rate.

*(English)*Zbl 0998.76036From the summary: Using direct numerical simulations of time-evolving annular mixing layers, which correspond to early development of round jets, we study the effect of compressibility on turbulence in free shear flows. Nine cases are considered with convective Mach numbers ranging from \(M_c=0.1\) to 1.8 and turbulence Mach numbers reaching as high as \(M_t=0.8\). Growth rates of the simulated mixing layers are suppressed with increasing Mach number as observed experimentally. Also, in accord with experiments, the mean velocity difference across the layer is found to be inadequate for scaling most turbulence statistics. We propose and validate an alternative scaling based on mean velocity difference across a typical large eddy, whose dimension is determined by two-point spatial correlations. Analysis of the budget of the streamwise component of Reynolds stress shows how the new scaling is linked to the observed growth rate suppression.

##### MSC:

76F50 | Compressibility effects in turbulence |

76F25 | Turbulent transport, mixing |

76F10 | Shear flows and turbulence |

76F65 | Direct numerical and large eddy simulation of turbulence |