Specific volume coupling and convergence properties in hybrid particle/finite volume algorithms for turbulent reactive flows

We investigate the coupling between the two components of a Large Eddy Simulation / Probability Density Function (LES/PDF) algorithm for the simulation of turbulent reacting flows. In such an algorithm, the Large Eddy Simulation (LES) component provides a solution to the hydrodynamic equations, whereas the Lagrangian Monte Carlo Probability Density Function (PDF) component solves for the PDF of chemical compositions. Special attention is paid to the transfer of specific volume information from the PDF to the LES code: the specific volume field contains probabilistic noise due to the nature of the Monte Carlo PDF solution, and thus the use of the specific volume field in the LES pressure solver needs careful treatment. Using a test flow based on the Sandia/Sydney Bluff Body Flame, we determine the optimal strategy for specific volume feedback. Then, the overall second-order convergence of the entire LES/PDF procedure is verified using a simple vortex ring test case, with special attention being given to bias errors due to the number of particles per LES finite volume (FV) cell. Suggested Reviewers: Daniel Haworth Dr. Professor, Mechanical Engineering, Pennsylvania State University [email protected] Performs research in this field Metin Muradoglu Dr. Associate Professor, Mechanical Engineering, Koc University [email protected] Performs research in this field Alexander Klimenko Dr. Reader in Fluid Dynamics and Thermodynamics, Mechanical Engineering, University of Queensland [email protected] Performs research in this field Significance and novelty of this paper This paper studies specific volume coupling between large eddy simulation (LES) and probability density function (PDF) components of an LES/PDF algorithm for turbulent reactive flows. Previous work has tackled this issue in the context of an overall algorithm for the simulation of turbulent reactive flows; the present work extends previous studies by examining the LES to PDF coupling error in detail, isolating it from other sources of numerical errors in an LES/PDF algorithm, and determining the optimal coupling strategy. A further original contribution of the present work is in the development of an LES/PDF coupling algorithm which allows for second-order accuracy of the overall code (with respect to both the grid size and time step); this second-order convergence is then verified numerically. Significance and Novelty of this paper