NACA 0012 Airfoil Example

A simple two-dimensional c-grid embedded in two box grids. Contains 3 zones and 74K grid points. This case uses the MESH translation and rotation variables to rotate the airfoil to 30 degrees angle of attack. The following two figures shows the final grid system. The symbols are plotted at each fringe point (which receives interpolation information from one of the other grids).

Download Example File

Input

NOTE: The minimal pegasus5 input file is that which is created by either the peg_setup script or the peg_in script. This minimal input file contains the $GLOBAL, $MESH, and $BCINP namelists, which, at a minimum, contain all the mesh names and all the boundary conditions for the flow problem.

For this case, the only necessary addition to the minimal input file is the increase to the value of the OFFSET input variable to OFFSET=5 for the box and box2 meshes. It is typically necessary to increase the value of OFFSET for box grids in 2D problems. In addition, the $GLOBAL namelist variable CNY was reduced to 3, since Y is the dummy direction for the 2D problem; this changes reduces the computer time spent in the hole-cutting operation. In addition, the airfoil was rotated to an angle of attack of 30 degrees changing the $MESH namelist for the wing grid: 


 $MESH
   NAME = 'wing',
    X0 = 0.5, Y0 = 0.0, Z0 = 0.25,
    XR = 0.5, YR = 0.0, ZR = 0.0, BETA = 30.0,
   $END

Images

  • Magenta grid lines: c-grid around airfoil

  • Green grid lines: inner box grid

  • Magenta symbols: box-grid points receiving data from airfoil

  • Green symbols: airfoil-grid points receiving data from box

Close-up of region near trailing edge of the airfoil