PEGASUS 5

PEGASUS 5 is a code which performs a pre-processing step for the Overset CFD method. The code prepares the overset volume grids for the flow solver by computing the domain connectivity database, and blanking out grid points which are contained inside a solid body.

PEGASUS 5 is the latest version of the PEGASUS series of mesh interpolation codes. The main purpose for the development of this latest version was to significantly decrease the number of user inputs required and to allow for easier operation of the code. The result is a process which is automatic for many flow analysis problems. All that is required from the user for most cases is an OVERFLOW input file and the volume grids. Some cases will require some additional input from the user.

Links to PEGASUS 5 Web resources

• PEGASUS 5 User's Manual

• PEGASUS 5 Current Status

• PEGASUS 5 Examples On-line

• Obtaining the software

Features of the PEGASUS 5 code

• Automatic minimum hole cutting: this only requires that the solid-wall boundary conditions form an enclosed surface.
  
  
• Hole optimization is achieved by effectively growing the minimum holes such that the interpolation boundary interfaces are optimized at a local cell-by-cell level.
  
  
• Outer boundaries are automatically detected, and interpolation boundary conditions are computed.
  
  
• Memory is dynamically allocated at run time. The code is written entirely in Fortran 90, and thus requires a Fortran 90 compiler.
  
  
• Restarting is similar to the UNIX "make" facility. As new meshes or inputs are added, PEGASUS will recognize these new changes and performs only the required operations.
  
  
• An internal projection process removes gaps found at randomly overset surface meshes, providing accurate interpolation in the boundary layer.
  
  
• Parallel option: the code can be compiled to use the Message Passing Interface (MPI) standard so that it can run simultaneously on distributed memory computers, enabling the processing of large cases in a matter of minutes.

PEGASUS Examples

Generic Business Jet

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.

Ball inside a duct

Red grid lines: hole in sphere grid cut by $HCUT NAME=duct_walls Green grid lines: hole in duct grid cut by $HCUT NAME=sphere_wall
Top view looking down on grid plane in the center-plane of the sphere Green symbols: sphere-grid points receiving data from duct Magenta symbols: duct-grid points receiving data from sphere