[Combas]

Dear all,

I have developed a tool to perform some post-processing. The aim of this tool is to allow the user:
- to get forces components for each surface (boundary)
- to get forces components for slices of surfaces (for example, for the computation of a wing, it is possible to get the forces distribution along the span)
Pressure and viscous forces are given separately.

Just to avoid to make raise some hope that could be disappointed, I give you the limits of this tool. It only works:
- for 3D meshes
- for RANS (Navier-Stokes) computations
- for triangular faces (for boundaries)
So it does not work for hexahedral meshes (but the code could probably be adapted to deal with such meshes). It does not work either for Euler computations, but the tool adaptation should be quite easy.

Unfortunately, this tool cannot be used directly for Navier-Stokes computations, since the actual SU2 output files does not contain enough data to compute forces. I have done some modifications in the SU2 source code to get all the data required to compute forces for every boundary faces. These modifications does not change anything in the computation, it only adds some data in the output file "surface_flow.csv". For those who want to know what I have changed, it is very easy: all my modifications begin with "Modif LBT" and end with "End Modif LBT".

Here is the process to follow to use this tool:
1) download the following files:
* ComputeLocalForces.py.gz
* output_structure.cpp.gz
* solver_direct_mean.cpp.gz
* solver_direct_tne2.cpp.gz
* solver_structure.hpp.gz
* solver_structure.inl.gz
Remark: the 2 last files are in the first reply to this post (since the number of files in attachment is limited to 5)
2) type in the terminal: gzip *.gz
3) put the .cpp files in the folder "SU2_CFD/src/" in your SU2 directory (replace the "old" files) and the solver_structure.hpp and solver_structure.inl in the folder "SU2_CFD/include/" (replace also the "old" files)
4) recompile the SU2 source code using the official procedure (no need to launch the ./configure). If you use linux, you should just do:
make clean
make
make install
(cf. http://adl-public.stanford.edu/docs/...on+from+Source)
5) If you want to analyse the result of a computation already done (with the official SU2 code), you just have to launch a new one (with the new SU2 version) with just 1 iteration for example ("EXT_ITER = 1" in the .cfg file)
You will get a new "surface_flow.csv" file that contains all the information needed to compute local forces.
The other file needed is the .su2 mesh file.
6) In the folder that contains the file ComputeLocalForces.py, type:
python ComputeLocalForces.py
You will have to answer some questions. If you want to perform an analysis by "slice" along a direction, be patient, it is the last question.

The computation of forces does not give exactly the same results as SU2 in the "history.csv" file, but they are very close. I think the main difference comes from the fact that SU2 uses normals given at mesh points, whereas I use normals to faces.

This tool does not allow to do complex things, but it is really helpful if you need to analyse the distribution of forces on you aircraft/wing/etc...

Laurent

[Combas]

I add the 2 missing files.

[demanosalvas]

It looks like a great tool, thanks for sharing it!

David