| A density-based; multi-block, computational model has been developed for large eddy simulation (LES) of reacting and nonreacting, single- and multi-phase, compressible turbulent flows in complex geometries and generalized coordinate systems. The spatially-filtered form of the compressible continuity, momentum, energy, and scalar equations are solved together with various subgrid turbulence closures. All spatial derivatives are approximated by a high-order compact differencing scheme and time derivatives are modeled via a low-storage, three-stage, third-order, Runge-Kutta method. Both Smagorinsky and algebraic RNG (renormalization group) subgrid scale models are employed. The nonreacting, single-phase large eddy and direct numerical simulations (DNS) results for isotropic turbulence, round/planar jets, and axisymmetric sudden expansion (dump combustor) flows are found to be in good agreement with those obtained via other validated high-order, numerical methods and with the available experimental data. The results obtained for nonreacting single-phase flows are described. A generalized Lagrangian/Eulerian, theoretical/numerical methodology is considered for LES of turbulent reacting flows in complex geometrical configurations via the filtered mass density function (FMDF) for subgrid-scale (SGS) combustion closure. The LES/FMDF method has some advantages over conventional methods. A novel numerical algorithm is developed for solving the Lagrangian equations which is much more efficient than similar unstructured grid system algorithms. The Lagrangian scheme is coupled with my high-order multi-block flow solver. This allows LES/FMDF to be extended to general coordinate systems. The consistency, conver gence, and accuracy of the FMDF and the Monte Carlo solution of its equivalent, stochastic differential equations are assessed for different flows. The consistency be tween Eulerian and Lagrangian fields is established for non-reacting isothermal and non-isothermal flows as well as reacting flows in a dump combustor. The results show good consistency between conventional LES and FMDF method for nonreacting and reacting cases. (Abstract shortened by UMI.)... |
