"Database of Large Eddy Simulation for Complicated Turbulent Flows"

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An aim of this project was to build a database for turbulent researches by using a large eddy simulation (LES) in a high accuracy approxmation with the latest turbulence models and numerical methods. The database was expected to include both the statistical variable data and the structural characteristics of turbulent flows.For developing the numerical methods and the subgrid scale (SGS) models for the large eddy simulation of various turbulent flows, some verification data were indicated for the latest proposed SGS models, a) a dynamic SGS model in the FDM and FEM formulation, b) a non-equilibrium SGS model proposed by Yoshizawa. According to these results, numerical programs were developed and improved to analyze the LES for seven objects ; 1) circular pipe flows with/with-out swirl, 2) a plane turbulent jet, 3) a wall impinging jet, 4) a channel flow with a cubic turbulent generator, 5) a flow around square cylinder and 6) a ventilation in the room with thermal stratified layr. Each object is researched with a physical or a numerical interest, a validation of LES by a boundary fitted coordinate (BFC) grid for case (1), development of numerical methods for boundary conditions for case (2), validations of SGS models for cases (3), (4) and (5), estimations of the affects by upwind schemes for convection terms for cases (4) and (5). For all cases, profiles of mean velocities, turbulent intensities and likes as statistical quantities are stored in the database of LES.Additionally, more detail data like a budget of turbulent energy compared with experimental data for the wall impinging jet (case (3)) and phase averaged quantities for the quasi-periodic turbulent flow (case (5)) were calculated. For analyzing the structural characteristics of these flows, two-and three-dimensional visualization were offered by the computer graphics and some by the animation, too.