| Abstrakt: |
This paper investigates the Reynolds number dependence of a turbulent mixing layer evolving from the Richtmyer–Meshkov instability using a series of direct numerical simulations of a well-defined narrowband initial condition for a range of different Reynolds numbers. The growth rate exponent $\theta$ of the integral width and mixed mass is shown to marginally depend on the initial Reynolds number $Re_0$ , as does the minimum value of the molecular mixing fraction $\varTheta$. The decay rates of turbulent kinetic energy and its dissipation rate are shown to decrease with increasing $Re_0$ , while the spatial distribution of these quantities is biased towards the spike side of the layer. The normalised dissipation rate $C_{\epsilon }$ and scalar dissipation rate $C_{\chi }$ are calculated and are observed to be approaching a high Reynolds number limit. By fitting an appropriate functional form, the asymptotic values of these two quantities are estimated as $C_{\epsilon }=1.54$ and $C_{\chi }=0.66$. Finally, an evaluation of the mixing transition criterion for unsteady flows is performed, showing that, even for the highest $Re_0$ case, the turbulence in the flow is not yet fully developed. This is despite the observation of a narrow inertial range in the turbulent kinetic energy spectra, with a scaling close to $k^{-3/2}$ , where k is the radial wavenumber. [ABSTRACT FROM AUTHOR] |
