by Jason Viggato

Flow-3D is a commercial computer software package designed for advanced analysis of fluid dynamics and heat transfer related problems. Some of its many uses are simulation of incompressible, slightly compressible, fully compressible flows, and thermal conduction in fluid and solid regions modeled as heat transfer between the regions. The Fluid flow capabilities include: Transient Navier-Stokes Equations in 1D, 2D, or 3D, choice of Cartesian or Cylindrical coordinates, Free Surfaces, Acoustic Wave propagation, Fully compressible Fluids at Subsonic, Transonic and Supersonic speeds, External and Internal Flow and Turbulence modeling through various methods, just to name a few. Heat transfer capabilities include: Free, Forced, or Mixed Convection, Conduction in Fluids and Solids, Solidification and Melting and Structure/Void Heat transfer. Boundary and Initial Conditions may also be imposed on any problem.

This Computational Fluid Dynamics code uses a combination of finite difference techniques along with numerous other numerical methods to provide the greatest efficiency and speed for analysis of intricate engineering problems. The package is made up of four separate codes. The first is the preprocessor, which performs the initial setup of properties, boundary conditions, obstacles and mesh generation. Control then moves over to the main processor to do the actual problem solving. After the computations are completed, the post processor uses data files that were written by the main processor to generate graphic displays. The final step is the image display program which reads the files and displays them according to the user's terminal setup.

Here at the supercomputing center FLOW-3D is currently setup up on atom (the Origin 2000). To run the code, you will need an account on the system (click here to apply for an NSCEE account). After obtaining an account, several changes to your setup will need to be made. First look in your .cshrc file to see if the following lines (or somethng very similar) are present:

               if ( -f ./.cshrc.local) then                   
                  source ./.cshrc.local

If it is not contact the system administrator. DO NOT make any modifications to this file. Now, if everything looks good, use an editor to create a file with the extension .flow3d

Sample problems may be run and output viewed. To run a sample problem copy all the files from /usr/local/flow3d/testprob to an area where you have write permission. Set the display of your terminal by using the command:

where host.domain is the full name of the terminal you are sitting at (for instance, **If you fail to do this step, the graphic display will not appear on your display.

Switch to the directory where you have copied the files and run the scripts by typing the following at the UNIX prompt (%):

% runpre
% runhyd
% runpost
% display

*Note: runall may be typed to execute runpre, runhyd and runpost at once, then use display to view output.

When in the pltfsi menu, choose the appropriate number to configure any desired plot options and use number 4 to display X Window plots.

For more information about FLOW-3D, see the Flow Science, Inc. web page.

Information used for the writing of this article was obtained from FLOW-3D manuals and the Flow Science web page. Graphics by FIELDVIEW.

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