Brief description of grid and map file

These are point matched structured O-O grids generated using ICEM

These grids do not meet all the gridding guidelines but have demonstrated good solution characteristics with both CFL3D and CFD++. The major deviation with the guidelines is with the far-field being approximately 50 chordlengths away.

The map file (connectivity file) is the standard form of TLNS3D multi-block grid type, it tells the boundary conditions to use, and the connectivity information among different blocks. When running CFL3D, there is a tlns3d to cfl3d conversion program to convert this map (or connectivity) file to cfl3d input file. See CFL3D user manual and TLNS3D paper by Dr. V. Vatsa. The grid format is in CFL3D standard format, available in the CFL3D User's Manual, NASA TM-1998-20844, or http://cfl3d.larc.nasa.gov/Cfl3dv6/cfl3dv6.html under the Version 5 Manual.

The grid file is an unformatted 64 bit binary file of the PLOT3D multiple grid form generated on workstation or PC, it consists of number of grid zones (blocks) and their dimension size, follows by the coordinates of each grid point, block by block, written out in PLOT3D three dimensional multiple grid format.

Grids sizes for both DPW-W1 and DPW-W2 
	Coarse grid      1.6 million
	Standard grid    4.2 million
        Medium Fine      8.6 million
 	Fine grid       14.8 million

The “fine” grids have been split to take advantage of multiple CPUs on PC Clusters.

Here is the segment of code to write the grid files

        open (10,file='Gfile',form='system')
        write(10) ngrids
c
        write(10) ((mm(j,i),j=1,3),i=1,ngrids)
c
        do 20 ig=1,ngrids
        nr = mm(1,ig)*mm(2,ig)*mm(3,ig)
        do 10 i=1,nr
        x(i) = xdum(i)
        y(i) = ydum(i)
        z(i) = zdum(i)
 10     continue
        write(10)(x(i),i=1,nr),(y(i),i=1,nr),(z(i),i=1,nr)
 20     continue
        close(10)
c

where	ngrids:			number of blocks	
	mm(1,n),mm(2,n),mm(3,n):I,J,K grid size in the block n, respectively
	x(i),y(i),z(i):		x,y,z coordinates for ith point in the block


Good Luck,

Ed

Edward N. Tinoco
edward.n.tinoco@boeing.com
Technical Fellow

Enabling Technology & Research
Mail Code 67-LK
Boeing Commercial Airplanes
P.O. Box 3707
Seattle, WA 98124
USA