The influence of initial conditions on turbulent mixing due to Richtmyer-Meshkov instability

B. Thornber, D. Drikakis, D. L. Youngs, R. J.R. Williams

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Abstract

This paper investigates the influence of different three-dimensional multi-mode initial conditions on the rate of growth of a mixing layer initiated via a Richtmyer-Meshkov instability through a series of well-controlled numerical experiments. Results are presented for large-eddy simulation of narrowband and broadband perturbations at grid resolutions up to 3 10 9 points using two completely different numerical methods, and comparisons are made with theory and experiment. It is shown that the mixing-layer growth is strongly dependent on initial conditions, the narrowband case giving a power-law exponent θ≈0.26 at low Atwood and θ≈0.3 at high Atwood numbers. The broadband case uses a perturbation power spectrum of the form P(k) k2 with a proposed theoretical growth rate of θ= 2/3. The numerical results confirm this; however, they highlight the necessity of a very fine grid to capture an appropriately broad range of initial scales. In addition, an analysis of the kinetic energy decay rates, fluctuating kinetic energy spectra, plane-averaged volume fraction profiles and mixing parameters is presented for each case.

Original languageEnglish
Pages (from-to)99-139
Number of pages41
JournalJournal of Fluid Mechanics
Volume654
DOIs
Publication statusPublished - 1 Jul 2010

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