Paper Title
COMPLETE STUDY ON DISCRETE TYPES OF GRIDS IN CFD: PREFERRED STRATEGYAbstract
The accuracy of the simulation is strongly depends on the quality of the grid. A good quality grid considering the flow physics leads to faster convergence and better solution. This paper deals with nonlinear FVM approach based on different kinds of meshing (using grids-C,O,H ).Theory is utilized to obtain the convergence rate, CPU time, coefficient of drag, coefficient of lift, lift/drag of the airfoil (NACA0012). The airfoil considered is studied with three different types of grids viz. O-grid, C-grid and H-grid and accordingly obtain the values of pressure, velocity and temperature. Airfoil is studied with two different flow regimes (i.e., 0.8M & 1.2M). Grid generation is the most critical part of the CFD modeling process and a major part of the computational effort is involved to satisfy certain conditions for valuable CFD results. Good mesh quality, grid alignment to the flow path, proper grid resolution near the boundary zones, etc. are the prerequisites for successful CFD simulation. The choice of finer grid resolution on a certain zone depends on characteristics like the non uniformity in the flow structure, presence of distinct motion type within a flow domain, steep gradient of the flow variables and fluid properties close to the zone, extent of the detail feature required etc. A Finite discretization is applied throughout the process in case of gridding. The computational method does not require any tuning of parameters. The solution obtained shows the good resolution of all flow phenomenon and are obtained by computational analysis. For CFD to be useful in conceptual design, the computational mesh must be built automatically. The generation of structured meshes, made of hexahedral blocks, requires extensive user interaction and skill to create an adequate grid.
KEYWORDS : Convergence, Airfoil, Descretization, Continuum.