Browsing by Subject "flux reconstruction/correction procedure via reconstruction"
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Item Analysis of Wake Structures Behind an Oscillating Square Cylinder Using Dynamic Mode Decomposition(AIAA Aviation Forum, 2016) Wang, Bin; Yu, MeilinA dynamic mode decomposition (DMD) algorithm has been used to analyze the vortex structures shedding from an oscillating square cylinder. The flow fields are simulated using a high-order accurate flux reconstruction/correction procedure via reconstruction (FR/CPR) method. The dominant dynamic modes from the wake vortex structures are then extracted from the DMD analysis. Effects of the Strouhal number and Reynolds number on the dynamic modes are studied. Results from DMD are also compared with those from proper orthogonal decomposition (POD). In this study, the capability of the two flow analysis techniques, namely DMD and POD, on capturing dominant vortex structures have been successfully demonstrated. Insights are gained into the flow physics induced by flow structure interaction.Item Direct Numerical Simulation of Shock/Boundary Layer Interaction over Surface Roughness Using the High-Oder FR/CPR-LLAV Method(AIAA SciTech Forum, 2016) Yu, MeilinA recently developed high-order accurate flux reconstruction/correction procedure via reconstruction (FR/CPR) method equipped with localized Laplacian artificial viscosity (LLAV) shock-capturing capability is used to simulate both two dimensional (2D) and three dimensional (3D) shock-boundary layer interaction (SBLI) at different Reynolds numbers with and without wall roughness. It is found that the method can effectively and sharply resolve both shock and boundary-layer separation features. From the SBLI simulation results, it is observed that surface roughness can change the interaction between the shock waves and the boundary layers. As a result, the surface heat transfer process can be substantially modified.Item A High-Order Dual-Time Stepping FR/CPR Method for Unsteady Incompressible Navier-Stokes Equations on Unstructured Moving Grids(AIAA SciTech Forum, 2016) Wang, Lai; Yu, MeilinA high-order accurate flux reconstruction/correction procedure via reconstruction (FR/CPR) method is developed to solve incompressible Navier-Stokes equations on unstructured moving grids. An artificial compressibility method is adopted to facilitate the common flux reconstruction on element interfaces. For unsteady flow simulations, a dual-time stepping method is used for temporal discretization. For simulations on deformable/moving grids, the Geometric Conservation Law (GCL) introduced in dynamic spatial coordinate transformation has been enforced. The newly developed method is verified with several steady and unsteady benchmark incompressible flow problems.Item A Preconditioned Flux Reconstruction/Correction Procedure via Reconstruction Formulation for Unsteady Low Mach Number Flows on Dynamic Unstructured Meshes(AIAA SciTech Forum, 2017) Wang, Lai; Yu, MeilinPreconditioning methods can signicantly decrease the condition number of the linear system resulted from the discretization of compressible Navier-Stokes equations at low Mach numbers by replacing the physical acoustic wave speeds with numerical ones. In the present study, the high-order accurate flux reconstruction/correction procedure via reconstruction (FR/CPR) method with low Mach number preconditioning is used to solve Navier-Stokes equations at low Mach numbers (Ma ~ O (10⁻³)). The dual time stepping method is used to handle un-steady flow simulations, wherein the second-order backward differentiation formula (BDF2) is adopted to discretize the temporal derivative with respect to the physical time. A simple modi cation of the preconditioning formulation is proposed to deal with dynamic meshes. Numerical results of several benchmark tests have demonstrated that the preconditioned FR/CPR method works well for low Mach number flows.