An adaptive finite element method with dynamic les for turbulent reactive flows

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A Vreman dynamic subgrid scale (SGS) large eddy simulation (LES) model is implemented in a predictor-corrector split h-adaptive finite element method (FEM) for modeling combustion. The use of h-adaptation provides a measurement of the actual error in the discretization, and can adjust spatial accuracy to control the error. By utilizing the dynamic model, laminar or turbulent flow can be automatically calculated. In this study, we try to validate this Vreman SGS LES model in just the fluid dynamics system by assuming all species are air and all results are compared with experimental data and RANS k – ω model. The model is tested by solving an 18° ramp at a Mach number of 2.25 as well as unsteady turbulent flow over a backward-facing step. The high Mach number ramp demonstrates the ability of the model to capture shocks and shock-wave/boundary layer interactions. In the high Reynolds number backward-facing step, large eddies are resolved without the requirement of a fine mesh, in contrast to DNS, although it is finer than a RANS model would require. The reattachment length and instantaneous flow results compare well with published simulations and experimental data. © 2016 by Begell House, Inc.