Business Jet Example

Download Example File

• bjet.tgz

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, only four additions were made to the minimal pegasus5 input file. The first of these additions is the use of the JINCLUDE and KINCLUDE inputs in the $MESH namelist to exclude the boundary planes which lie on the symmetry plane of the problem for the meshes outerbox, fusebox, fuselage, filletsymmetry, and fuselagefillet. (This step will be automated in a future release).

The second modification was to increase the global value of OFFSET from 0 to 1, and to set the value of OFFSET=2 for the nacelle mesh. This was done to improve the quality of the automatic hole cutting: the size of the holes in the box grids needed to be increased, and some grid points were being left inside some of the thin trailing edges of the wing, pylon, and nacelle.

The third addition was necessary to remove a bad automatic hole which was being cut in surface of the wingfillet mesh. (See details of this problem with the automatic hole-cutting algorithm). The $REGION and $VOLUME namelists are used to eliminate any holes in and near the surface of the wingfillet mesh with the following:

 $REGION NAME = 'wingfillet_nocut',
    TYPE = 'UNBL',
    ISPARTOF = 'wingfillet',
                         $END
 $VOLUME ISPARTOF = 'wingfillet_nocut',
    JRANGE = 1,-1,
    KRANGE = 1,-1,
    LRANGE = 1,15,
                         $END

The fourth addition was simply the removal of the first three inboard planes (k=1,2,3) of the wing mesh. This part of the wing was deep inside the fuselage and is completely unnessecary. The automatic hole-cutting in pegasus5 removed most, but not all of these grid points. (A more efficient method fix would be to remove these grid points from the original X_DIR/wing.x file.) This was accomplished within pegasus5 using these lines:

 $REGION ISPARTOF = 'wing',
     NAME = 'trimwingend',
     TYPE = 'HOLE',
                           $END
 $VOLUME 
     ISPARTOF = 'trimwingend',
     JRANGE = 1,-1,
     KRANGE = 1, 3,
     LRANGE = 1,-1,
                           $END

Images

Blue grid lines: outerbox grid Cyan grid lines: fusebox grid Red symbols: points receiving data from body Black symbols: points receiving data from fusebox Blue symbols: points receiving data from outerbox
Green grid lines: fuselage grid Cyan grid lines: boxbody grid Red symbols: points receiving data from body Black symbols: points receiving data from boxbody Blue symbols: points receiving data from boxouter NOTE: the input file specifies a global value of OFFSET=1 which results in good holes for all of the box grids.
Symbols indicate ORPHAN points PEGASUS5 leaves only 71 ORPHAN points in the entire configuration. Most of these are located inside the thin trailing edges of the wing, pylon, and nacelle.