Parallelization of UDFs in ANSYS FLUENT

Parallelization of UDFs in ANSYS FLUENT

by

Subhransu Majhi

Most of the UDFs that we create in-house are programmed for serial mode of ANSYS FLUENT since it only involves basic coding in C program with required marcos and our UDF is ready. However, parallel mode of ANSYS FLUENT has tremendously reduced the simulation time and hence it becomes very important for us to modify our serial UDFs to support parallel processing as well. But, here comes the challenge for us (mechanical engineers) to write down a parallel processing code in C program.

See the full-post here from learnCAx.com SOURCE

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Some OpenSource CFD and Mesh codes

Some OpenSource CFD and Mesh codes

This is part 2 of the post Open Sourced CFD and Mesh codes

1. Xfoil: 2D viscous/inviscid interactive code. http://web.mit.edu/drela/Public/web/xfoil/ . More of a low computational cost design code.
2. AVL: 3D vortex lattice code: http://web.mit.edu/drela/Public/web/avl/ . Another code with low computational overhead.
3. OpenFoam: 3D, very versatile code. Active user community. Various pre-build packages as well. http://www.openfoam.com/
4. XLR5: http://xflr5.sourceforge.net/xflr5.htm wings/aerofoil code. Again aimed more at the low computational effort/disgn scenario.
5. FreeCFD: open source CFD project. . 3D implicit density based solver. Site also has a forum. (Site link expired, will update newer link as sonn as we find it)
6. Gerris : http://gfs.sourceforge.net/wiki/index.php/Main_Page . supported by National Institute of Water and Atmospheric research, lots of multi phase stuff, immersed boundary conditions etc. Good users guide/example cases.
7. SU stanford univeristy OpenSource CFD code http://su2.stanford.edu/
8. Code Saturn: http://code-saturne.blogspot.co.uk/ finite volume CFD
9. Incompact3D by Laizet  Incompact3d is based on a Cartesian mesh. The use of such a simplified mesh offers the opportunity to implement high-order compact schemes in the code for the spatial discretisation whilst an Immersed Boundary Method (IBM) allows the implementation of any solid wall/bluff body geometry inside the computational domain. The main originality of the code is that the Poisson equation (to ensure the incompressibility) is fully solved in the spectral space via the modified wave number formalism, no matter what the boundary conditions are (periodic, free-slip, no-slip, inflow/outflow, etc.). Note finally that the pressure mesh is staggered from the velocity one by half a mesh to avoid spurious pressure oscillations that can be introduced by the IBM. (Thanks Sulfi for pointing it out)
10. OpenFOAM on Windows by Nishit Joseph, Cross compiled binaries of OpenFOAM-2.1.x using OpenMPI. More on his sourceforge page. (Thanks Santosh for pointing it out)
11. A nice list of mesh generators LINK

Mesh generators:

1. Qhull: http://www.qhull.org/
2. Triangle: http://www.cs.cmu.edu/~quake/triangle.html
3. Gmsh: http://geuz.org/gmsh/ (uses tetgen and netgen algorithms)
4. Tetgen: http://tetgen.berlios.de/
5. netgen: http://www.hpfem.jku.at/netgen/
6. sumo: http://www.larosterna.com/sumo.html - highly recommend this! comes with many geometries already loaded of full aircraft. Volume mesh generation via tetgen.
7. http://engits.eu/en/engrid: volume grid generation with CFD in mind.

Thanks to Laurence Griffiths University of Bristol, for the list !

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Scientific development in Windows : Setting Up

Scientific development in Windows : Setting Up

Yes ! reluctantly I have been fiddling with Windows for scientific development. I am presently involved in a project, in collaboration with some big guys (in terms of coding). Windows happens to used by one of the developers, although the parallel jobs are submitted on Scientific Linux clusters. So, I thought why not try it out. phew.

There are two ways to go about this, one the paid way and two the free way ! Paid ways are many which include the use of Microsoft Visual Studio with Intel Visual FORTRAN and many others out there.

However, there are other ways to go about this in the open-source (free) community. I have used only one of them, so feel free to throw-in your ideas/experience as well. As, I have been used to the command-line and makefile in Linux, I am comfortable in working with some transition between Linux & Windows.

For the compilers, I am using Cygwin (takes a lot of time & space, nearly 20gigs to install - I left it for a full night to install, also make sure to include the compilers, kde-openbox, parallel compilers and any libraries / applications you might need like gnuplot, vim, etc) but there are other alternatives as well. It is to be noted that Cygwin has MPI support as well, and I am using eclipse as an editor and I don't want to be bothered at the moment to setup eclipse properly and use Cygwin compilers directly.

Well, that's it for some start !

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