Depends upon type of discretization scheme and

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Depends upon type of discretization scheme and applicationSchemeFinite differences: structuredFinite volume or finite element: structured or unstructuredApplicationThin boundary layers best resolved with highly-stretched structured gridsUnstructured grids useful for complex geometriesUnstructured grids permit automatic adaptive refinement based on the pressure gradient, or regions of interest (FLUENT)
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36Grid Resolution
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37Grid generation and transformationGrids designed to resolve important flow features which are dependent upon flow parameters (e.g., Re)Commercial codes such as Gridgen, GambitFor research code, grid generated by one of several methods (algebraic vs. PDE based, conformal mapping)For complex geometries, body-fitted coordinate system will have to be applied (next slide). Grid transformation from the physical domain to the computational domain will be necessarySample grid established by Gambit of FLUENT
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38Grid transformationyxooPhysical domainComputational domainxxfffffxxxyyfffffyyyTransformation between physical (x,y,z) and computational (,,z) domains, important for body-fitted grids. The partial derivatives at these two domains have the relationship (2D as an example)
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39Software and resourcesCFD software was built upon physics, modeling, numerics.Two types of available softwareCommercial (e.g., FLUENT, CFX, Star-CCM, COMSOL)Research (e.g., CFDSHIP-IOWA, U2RANS)More information on CFD can be got on the following website:CFD Online: CFD softwareFLUENT: COMSOL CD-adapco: Grid generation softwareGridgen: GridPro: Visualization softwareTecplot: Fieldview:
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