NuWTun compressible flow solver

Contents

• src-flo : Flow solver files
• src-adj : Adjoint solver files, NOT FINISHED YET
• examples: Example test cases
• docs : Manual, license, etc.

Compiling

You will need a fortran 90 compiler since dynamic memory allocation is used. Compilation has been tested with gfortran. Set your compiler and flags in makefile.in and define a shell variable called NUWTUN_HOME which contains the absolute path to the root directory. You also need the archive tool "ar"; this should be available on most systems. To compile the flow solver execute the following commands at the shell prompt:

cd $NUWTUN_HOME/src-flo
make

Call-tree

If you have ftnchek, then you can generate a call-tree inside the docs/tree/src-flo directory. Inside the directory src-flo type make tree to generate the tree. This has been tested to work only on GNU/Linux. You can change the location where the call-tree is stored by changing the CTDIR variable in makefile.in to appropriate value.

Visualization

Nuwtun can output the solution in plot3d format. Plot3d files can be read by the following visualization softwares:

• Tecplot: Commercial software, but probably the best one.
• Paraview: Free software, based on VTK, can read only grid and solution files, not the function file.
• Mayavi: Free software, similar to Paraview and is based on VTK. Only 3-D files can be read.
• Calculix: Free software, can read both 2-d and 3-d files, only formatted, can read grid, solution and function files. It is quite good for 2-D.

Running flow solver

Compile

cd $NUWTUN_HOME
make flo

Run

$NUWTUN_HOME/src-flo/nuwtun_flo < flo.in > flo.log 2>&1 &

Monitor the run with tail

tail -f flo.log

Some output files:

• fort.17: residual history
• fort.18: cl,cd history
• fort.19: some global results, useful for optimization

Plot convergence history (requires gnuplot)

gnuplot $NUWTUN_HOME/src-utl/nwthist.gnu

This creates files clcd.eps and res.eps

Postprocessing

The output is in plot3d format which can be viewed using Calculix cgx or Paraview.

There are some programs in src-utl to process the output.

• extract: This reads flo.log to extract some surface data.
• ext2cp: Run this after running extract
• plot2vtk_2d: Writes a vtk file for 2d (use Visit/Paraview to see vtk file)
• plot2vtk_3d: Writes a vtk file for 3d (use Visit/Paraview to see vtk file)

Run make inside this directory to compile all the programs.

Grid deformation tools

src-grd has radial-basis function based deformation tools for shape and grid. See the README file inside this directory.

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• Origin: https://codeberg.org/cpraveen/nuwtun
• Mirror: https://git.sr.ht/~cpraveen/nuwtun
• Mirror: https://github.com/cpraveen/nuwtun