حل عددي جريان آشفته به روش گردابه هاي بزرگ با استفاده از مدل زيرشبكه ديناميكي موضعي

Simulation of Turbulent Flow using LES Method with Localized Dynamic Sub Grid Scale Model

In this article sub-grid modeling of Smagorinsky and Localized Smagorinsky Models are investigated. In modeling sub-grid scales, it is necessary to determine the Smagorinsky coefficient which is an experimental constant. Dynamic Models are developed to estimate this value more efficiently. In this research, the test filter is Gaussian, numerical method is based on the finite volume scheme, and a SIMPLE algorithm is used to evaluate the pressure. To perform computations on a personal computer, value of Reynolds number had chosen enough low to make a two dimensional modeling and comparison with respective experimental results possible. Comparison of numerical results shows high accuracy of the localized dynamic models. More numerical investigations reveal that although localized dynamic models need more computing time, but the higher resolution of the method makes it possible to use a coarser grid and hence compensate the extra CPU time. Keywords: Large Eddy Simulation, Filter, Smagorinsky SGS Model, Dynamic SGS Model, Localized Dynamic SGS Model, Turbulent Flow.