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need to be developed using the Massage Passing Interface (MPI) Standard to transfer data between different blocks.•Post-processing: 1. Visualize the CFD results (contour, velocity vectors, streamlines, pathlines, streak lines, and iso-surface in 3D, etc.), and 2. CFD UA: verification and validation using EFD data (more details later)•Post-processing usually through using commercial software
27Types of CFD codes•Commercial CFD code: FLUENT, Star-CD, CFDRC, CFX/AEA, etc.•Research CFD code: CFDSHIP-IOWA•Public domain software (PHI3D, HYDRO, and WinpipeD, etc.)•Other CFD software includes the Grid generation software (e.g. Gridgen, Gambit) and flow visualization software (e.g. Tecplot, FieldView)CFDSHIPIOWA
28CFD Educational InterfaceLab1: Pipe FlowLab 2: Airfoil FlowLab3: DiffuserLab4: Ahmed car1. Definition of “CFD Process” 2. Boundary conditions3. Iterative error4. Grid error5. Developing length of laminar and turbulent pipe flows.6. Verification using AFD7. Validation using EFD1. Boundary conditions2. Effect of order of accuracy on verification results3. Effect of grid generation topology, “C” and “O” Meshes4. Effect of angle ofattack/turbulent models on flow field5. Verification and Validation using EFD1. Meshing and iterative convergence2. Boundary layer separation3. Axial velocity profile4. Streamlines5. Effect of turbulence models6. Effect of expansionangle and comparisonwith LES, EFD, andRANS.1. Meshing and iterativeconvergence2. Boundary layer separation3. Axial velocity profile4. Streamlines5. Effect of slant angle andcomparison with LES, EFD, and RANS.
29CFD process•Purposes of CFD codes will be different for different applications: investigation of bubble-fluid interactions for bubbly flows, study of wave induced massively separated flows for free-surface, etc.•Depend on the specific purpose and flow conditions of the problem, different CFD codes can be chosen for different applications (aerospace, marines, combustion, multi-phase flows, etc.)•Once purposes and CFD codes chosen, “CFD process” is the steps to set up the IBVP problem and run the code:1. Geometry2. Physics 3. Mesh 4. Solve 5. Reports 6. Post processing
31Geometry•Selection of an appropriate coordinate•Determine the domain size and shape•Any simplifications needed? •What kinds of shapes needed to be used to best resolve the geometry? (lines, circular, ovals, etc.)•For commercial code, geometry is usually created using commercial software (either separated from the commercial code itself, like Gambit, or combined together, like FlowLab)•For research code, commercial software (e.g. Gridgen) is used.