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LARGE EDDY SIMULATION OF COMPRESSIBLE TURBULENT MIXING

Ben Thornber
Fluid Mechanics and Computational Science Group, Department of Aerospace Sciences, School of Engineering, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK

Andrew Mosedale
Fluid Mechanics and Computational Science Group Department of Aerospace Sciences Cran eld University MK43 0AL UK

Dimitris Drikakis
Fluid Mechanics and Computational Science Group, Department of Aerospace Sciences, School of Engineering, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK

Abstrakt

This paper presents implicit large eddy simulation of compressible turbulent mixing produced by a shock wave passing through a perturbed gas interface. Two diff erent initial conditions are employed, three diff erent grid sizes for each initial condition, and two very high order numerical methods. Solutions are gained which are reasonably grid converged, and approach a quasi self-similar state. It is shown that the choice of initial conditions aff ect signifi cantly the growth of the turbulent mixing zone, and the plane averaged mixing parameters. The high wavenumber initial perturbation leads to a smoother mean volume fraction profile, and a lower growth rate. Employing low wavenumber perturbations gives a faster growth rate due to the presence of long wavelengths which grow on a longer timescale. The paper discusses further the behaviour of resolved turbulent kinetic energy, kinetic energy spectra, and self-similarity of plane averaged quantities.