Modeling and simulation of mixing flows are rife with challenges. These complex variable-density problems can feature transient flow, onset and development of turbulence, non-equilibrium turbulence, density fluctuations, and production of turbulence kinetic energy by shear and buoyancy mechanisms, which are difficult to parameterize with one-point RANS closures. Hence, we have been working on extending the bridging partially-averaged Navier-Stokes equations (PANS) method to material-mixing problems. In this presentation, we discuss the current state of our work and present the framework to extend PANS closures to such a class of variable-density problems. The Taylor-Green Vortex and Rayleigh-Taylor benchmark flows are predicted to illustrate the potential of the model. The results show that the PANS method can accurately predict these variable-density flows at a fraction of the cost of Large-Eddy or Direct Numerical Simulations (LES and DNS). Such a cost reduction can exceed a factor of fourteen for the TGV flow. A new verification and validation technique is also discussed.
*Los Alamos National Laboratory (LANL) is operated by TRIAD National Security, LLC for the US DOE NNSA. This research was funded by LANL Mix and Burn project under the DOE ASC, Physics and Engineering Models program.
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Publication:[1] - F. S. Pereira, F. F. Grinstein, D. M. Israel, R. Rauenzahn, and S. S. Girimaji - Modeling and simulation of transitional Taylor-Green vortex flow with partially averaged Navier-Stokes equations. Phys. Rev. Fluids 6, 054611; [2] - F. S. Pereira, F. F. Grinstein, D. M. Israel, R. Rauenzahn, and S. S. Girimaji - Partially averaged Navier-Stokes closure modeling for variable-density turbulent flow (accepted); [3 - F. S. Pereira, F. F. Grinstein, D. M. Israel, R. Rauenzahn, and S. S. Girimaji - Modeling and simulation of transitional Rayleigh-Taylor flow with partially averaged Navier-Stokes equations. (submitted);
