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Grids - Airfoil Near-Wake Case

Note that these grids are similar to those originally developed for this airfoil, except that the current grids have farfield extent of 500c (the original grids had farfield extent of only 20c).

A series of 5 nested 2-D grids are provided for the Nakayama Model-A airfoil (with sharpened trailing edge). Each coarser grid is exactly every-other-point of the next finer grid, ranging from the finest (L1) 2369 x 449 (divided into two zones of 673 x 897 and 1025 x 449) to the coarsest (L5) 149 x 29 grid (divided into two zones of 43 x 57 and 65 x 29). The finest grid has minimum spacing at the wall of y=2.5 x 10^-6, giving an approximate average y+ between 0.1 and 0.2 over the airfoil at the Reynolds number run. The grid is stretched in the wall-normal direction, and the clustering is maintained in the wake region. The original topology is a so-called "C-grid," with the grid wrapping around the airfoil from downstream farfield, around the lower surface to the upper, then back to the downstream farfield again; the grid connects to itself in a 1-to-1 fashion in the wake. However, in this case the grid has been reconfigured and divided into 2 zones, the first covering the entire wake region, and the second covering the airfoil. There are 1025 points on the airfoil surface on the finest grid (65 points on the coarsest grid). There are 673 points along the wake from the airfoil trailing edge to the outflow boundary on the L1 grid (43 points on the L5 grid). The figures below show two views of the L3 grid (169 x 225 and 257 x 113).

Note: be sure to use double precision when reading the grids!

STRUCTURED VERSIONS OF GRIDS

PLOT3D Files

The structured PLOT3D grids are given in two different ways, as 2-D grids (x-y plane) or as 3-D grids (two identical x-z planes, separated by a distance y=1, giving one spanwise cell for all grid levels). You may use whichever is more convenient for your particular application.

Format for the structured 2D grids is PLOT3D-type, formatted, MG, 2D (nbl=1) - note that you must use double precision when reading! :

      read(2,*) nbl
      read(2,*) (idim(n),jdim(n),n=1,nbl)
      do n=1,nbl
        read(2,*) ((x(i,j,n),i=1,idim(n)),j=1,jdim(n)),
     +            ((y(i,j,n),i=1,idim(n)),j=1,jdim(n))
      enddo

Download the 2-D version of the grids in PLOT3D format here:

• (2-D) 673x897 and 1025x449 (1025 points on airfoil surface) (gzipped) (15.3 MB)
• (2-D) 337x449 and 513x225 (513 points on airfoil surface) (gzipped) (3.9 MB)
• (2-D) 169x225 and 257x113 (257 points on airfoil surface) (gzipped) (< 1 MB)
• (2-D) 85x113 and 129x57 (129 points on airfoil surface) (gzipped) (< 1 MB)
• (2-D) 43x57 and 65x29 (65 points on airfoil surface) (gzipped) (< 1 MB)

Format for the structured 3D grid is PLOT3D-type, formatted, MG, 3D (nbl=1, and idim in this case is 2) - note that you must use double precision when reading! :

      read(2,*) nbl
      read(2,*) (idim(n),jdim(n),kdim(n),n=1,nbl)
      do n=1,nbl
        read(2,*) (((x(i,j,k,n),i=1,idim(n)),j=1,jdim(n)),k=1,kdim(n)),
     +            (((y(i,j,k,n),i=1,idim(n)),j=1,jdim(n)),k=1,kdim(n)),
     +            (((z(i,j,k,n),i=1,idim(n)),j=1,jdim(n)),k=1,kdim(n))
      enddo

Download the 3-D version of the grids in PLOT3D format here:

• (3-D) 2x673x897 and 2x1025x449 (2x1025 points on airfoil surface) (gzipped) (20.6 MB)
• (3-D) 2x337x449 and 2x513x225 (2x513 points on airfoil surface) (gzipped) (5.2 MB)
• (3-D) 2x169x225 and 2x257x113 (2x257 points on airfoil surface) (gzipped) (1.3 MB)
• (3-D) 2x85x113 and 2x129x57 (2x129 points on airfoil surface) (gzipped) (< 1 MB)
• (3-D) 2x43x57 and 2x65x29 (2x65 points on airfoil surface) (gzipped) (< 1 MB)

If desired, example Neutral Map Files associated with 3-D version of the grids are given here (these files specify grid indices associated with each boundary condition - see The Neutral Map File):

• Neutral Map File for (3-D) 2x673x897 and 2x1025x449
• Neutral Map File for (3-D) 2x337x449 and 2x513x225
• Neutral Map File for (3-D) 2x169x225 and 2x257x113
• Neutral Map File for (3-D) 2x85x113 and 2x129x57
• Neutral Map File for (3-D) 2x43x57 and 2x65x29

CGNS Files

The structured grids are also available as CGNS files (3-D versions only, with two identical x-z planes, separated by a distance y=1, giving one spanwise cell for all grid levels). Note that the BCs written inside the CGNS files are for guidance only, and may not reflect the appropriate BCs needed for your application. To read/write CGNS files, (free) software may be necessary if your pre/post-processing tools do not already handle it. See: CGNS Website for details.

Download the 3-D version of the grids in CGNS format (gzipped) here:

• (3-D) 2x673x897 and 2x1025x449 (2x1025 points on airfoil surface) (gzipped) (14.6 MB)
• (3-D) 2x337x449 and 2x513x225 (2x513 points on airfoil surface) (gzipped) (3.7 MB)
• (3-D) 2x169x225 and 2x257x113 (2x257 points on airfoil surface) (gzipped) (< 1 MB)
• (3-D) 2x85x113 and 2x129x57 (2x129 points on airfoil surface) (gzipped) (< 1 MB)
• (3-D) 2x43x57 and 2x65x29 (2x65 points on airfoil surface) (gzipped) (< 1 MB)

UNSTRUCTURED VERSIONS OF GRIDS

CGNS and AFLR3 Files

The unstructured versions of the same grids are all given as CGNS and AFLR3 (UGRID) files. Note that the BCs written inside the CGNS files are for guidance only, and may not reflect the appropriate BCs needed for your application. To read/write CGNS files, (free) software may be necessary if your pre/post-processing tools do not already handle it. See: CGNS Website for details.

The unstructured grids are all given as 3-D grids (two identical x-z planes, separated by a distance y=1, giving one spanwise cell for all grid levels). They are given as hexahedra (quadrilaterals in the x-z plane). Note that duplicate gridpoints in the C-mesh wakes are removed when writing the structured grids as unstructured.

Download the unstructured CGNS grids (gzipped) as 3-D hexahedra (quadrilaterals in x-z plane) here:

• (3-D) unstructured quad version of 2x673x897 and 2x1025x449 (2x1025 points on airfoil surface) (gzipped) (52.0 MB)
• (3-D) unstructured quad version of 2x337x449 and 2x513x225 (2x513 points on airfoil surface) (gzipped) (12.5 MB)
• (3-D) unstructured quad version of 2x169x225 and 2x257x113 (2x257 points on airfoil surface) (gzipped) (3.1 MB)
• (3-D) unstructured quad version of 2x85x113 and 2x129x57 (2x129 points on airfoil surface) (gzipped) (< 1 MB)
• (3-D) unstructured quad version of 2x43x57 and 2x65x29 (2x65 points on airfoil surface) (gzipped) (< 1 MB)

Download the unstructured AFLR3 grids (gzipped) as 3-D hexahedra (quadrilaterals in x-z plane) here:

• (3-D) unstructured quad version of 2x673x897 and 2x1025x449 (2x1025 points on airfoil surface) (gzipped) (52.0 MB)
• (3-D) unstructured quad version of 2x337x449 and 2x513x225 (2x513 points on airfoil surface) (gzipped) (12.5 MB)
• (3-D) unstructured quad version of 2x169x225 and 2x257x113 (2x257 points on airfoil surface) (gzipped) (3.1 MB)
• (3-D) unstructured quad version of 2x85x113 and 2x129x57 (2x129 points on airfoil surface) (gzipped) (< 1 MB)
• (3-D) unstructured quad version of 2x43x57 and 2x65x29 (2x65 points on airfoil surface) (gzipped) (< 1 MB)

Return to: 2D Airfoil Near-Wake Verification Case Intro Page

Return to: Turbulence Modeling Resource Home Page

Recent significant updates:
10/02/2023 - added AFLR3 (UGRID) versions of unstructured grids

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Last Updated: 10/02/2023