OpenFOAM vs code-saturn vs FreeCFD vs ...

Xwang · October 13, 2009, 15:38

Which open source Navier Stokes solver do you suggest for external aerodynamic calculation (airplanes (subsonic, transonic and supersonic), cars (maybe also internal cooling flows))?
In case other is selected, can you post the name of the code and some useful link?
Thank you,
Xwang

Ps for the preprocessing I think I'll use Salome.

praveen · October 13, 2009, 22:25

Openfoam does not seem to have good support for compressible flows, especially with strong shocks. Thats what I have gleaned from browsing through it but I would like to hear from others. I have no experience with code-saturne.

I would have recommended freecfd but their 3-d implementation is not complete; they are trying out a new limiter scheme which does not seem to have been finished for 3-d. But if this situation has changed and the turbulence models are also working, then freecfd would be very good.

esozer · October 17, 2009, 09:48

Praveen is right. Limiter implementation in Free CFD currently has some problems for 3D. I took a break from developing Free CFD to finish my dissertation. I will soon continue. I actually changed the limiter implementation and fixed the issue already. It is rather trivial. I am now testing and adding a few more features for the next release of Free CFD. Tune in to www.freecfd.com for an announcement.

Turbulence models, on the other hand, are working well.

I suggest you just try the example cases that comes with the code to judge if it is right for you. After all, I am sure the other codes would work for you just as well. It is a matter of personal taste in the end.

Xwang · July 28, 2011, 15:07

What is your opinions after two years?
The majority of polls votes are for openFoam, but the comment are all for freeCFD.
Thank you,
Xwang

Martin Hegedus · July 28, 2011, 16:32

My understanding is that since OpenFOAM is not a coupled method it can not handle steady state supersonic flow, i.e. the solution does not converge. This would also mean that OpenFOAM can not handle supersonic pockets. There was an effort, AeroFOAM, to create a coupled solver for such flow, but I gather it is not supported by anyone. In the 2010 OpenFOAM workshop there was a paper on SIMPLE vs. Coupled, http://web.student.chalmers.se/group...SlidesOFW5.pdf

praveen · July 28, 2011, 22:11

Quote:

Originally Posted by Martin Hegedus

My understanding is that since OpenFOAM is not a coupled method it can not handle steady state supersonic flow, i.e. the solution does not converge. This would also mean that OpenFOAM can not handle supersonic pockets.

This is possible with rhoCentralFoam, which is the only truly compressible solver available in openfoam.

Martin Hegedus · July 28, 2011, 23:24

Quote:

Originally Posted by praveen

This is possible with rhoCentralFoam, which is the only truly compressible solver available in openfoam.

In the past I have not been able to get rhoCentralFoam to converge to machine zero for transonic (i.e. has supersonic pockets) or low speed supersonic flow. For transonic flow the solution residuals asymptote to a value and for supersonic flow it blows up. When compared to other answers, for example these results http://www.hegedusaero.com/examples/.../Vassberg.html, rhoCentralFoam did not compare well. Note, I did not publish my rhoCentralFoam results on that page. That's not to say rhoCentralFoam doesn't give good results when used by someone who knows the ins and outs. I was just not able to get it to work.

I see you've done some work with NACA 0012. Were you able to converge the results to machine zero? Also, what conditions did you run it with (mach, alpha, reynolds number, turbulence model, and outer boundary conditions) and what were the CL and CD results. If you give me that information I'll run my solver on it and see how it compares.

Martin Hegedus · July 29, 2011, 00:41

After digging up information on rhoCentralFoam I'm uncertain it does turbulence modeling. Does rhoCentralFoam include turbulence modeling?

praveen · July 29, 2011, 08:17

rhoCentralFoam does only global time stepping. So getting convergence for steady state problems will need too many iterations. I have not looked at how well it converges, since it does not seem to calculate residuals. I am trying to implement local time stepping and run it in parallel.

It does not seem to have turbulence models. It should not be difficult to add it though.

Martin Hegedus · July 29, 2011, 11:14

I can't remember the details, (I tried different solvers, bcs, etc.), but for rhoCentralFoam I believe I created a code to compare the solutions at two adjacent (n and n+1) time steps to get residuals. The runs were inviscid and the grid was coarse. Anyway, unless I can find my runs, or recreate them, I should not say much.

View Poll Results: Which open source code for eternal aerodynamics?
OpenFOAM	45	72.58%
Code-saturn	8	12.90%
Free CFD	6	9.68%
Other	3	4.84%
Voters: 62. You may not vote on this poll

October 13, 2009, 15:38	OpenFOAM vs code-saturn vs FreeCFD vs ...	#1
Xwang Member Join Date: Jun 2009 Posts: 38 Rep Power: 16	Which open source Navier Stokes solver do you suggest for external aerodynamic calculation (airplanes (subsonic, transonic and supersonic), cars (maybe also internal cooling flows))? In case other is selected, can you post the name of the code and some useful link? Thank you, Xwang Ps for the preprocessing I think I'll use Salome.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
OpenFOAM - Validation of Results	Ahmed	OpenFOAM Running, Solving & CFD	10	May 13, 2018 18:28
Small 3-D code	Zdravko Stojanovic	Main CFD Forum	2	July 19, 2010 10:11
Self implemented code is not running in parallel	michi	OpenFOAM Running, Solving & CFD	2	November 6, 2008 05:09
Musig code in OpenFoam	in_flu_ence	OpenFOAM Running, Solving & CFD	1	February 25, 2007 16:47
OpenFOAM Version 1.3 Released	OpenFOAM discussion board administrator	OpenFOAM Announcements from ESI-OpenCFD	0	March 29, 2006 18:06

October 13, 2009, 22:25		#2
praveen Super Moderator Praveen. C Join Date: Mar 2009 Location: Bangalore Posts: 342 Blog Entries: 6 Rep Power: 18	Openfoam does not seem to have good support for compressible flows, especially with strong shocks. Thats what I have gleaned from browsing through it but I would like to hear from others. I have no experience with code-saturne. I would have recommended freecfd but their 3-d implementation is not complete; they are trying out a new limiter scheme which does not seem to have been finished for 3-d. But if this situation has changed and the turbulence models are also working, then freecfd would be very good.

October 17, 2009, 09:48		#3
esozer New Member Emre Join Date: Oct 2009 Location: Ann Arbor, MI Posts: 12 Rep Power: 16	Praveen is right. Limiter implementation in Free CFD currently has some problems for 3D. I took a break from developing Free CFD to finish my dissertation. I will soon continue. I actually changed the limiter implementation and fixed the issue already. It is rather trivial. I am now testing and adding a few more features for the next release of Free CFD. Tune in to www.freecfd.com for an announcement. Turbulence models, on the other hand, are working well. I suggest you just try the example cases that comes with the code to judge if it is right for you. After all, I am sure the other codes would work for you just as well. It is a matter of personal taste in the end.

July 28, 2011, 15:07		#4
Xwang Member Join Date: Jun 2009 Posts: 38 Rep Power: 16	What is your opinions after two years? The majority of polls votes are for openFoam, but the comment are all for freeCFD. Thank you, Xwang

July 28, 2011, 16:32		#5
Martin Hegedus Senior Member Martin Hegedus Join Date: Feb 2011 Posts: 500 Rep Power: 19	My understanding is that since OpenFOAM is not a coupled method it can not handle steady state supersonic flow, i.e. the solution does not converge. This would also mean that OpenFOAM can not handle supersonic pockets. There was an effort, AeroFOAM, to create a coupled solver for such flow, but I gather it is not supported by anyone. In the 2010 OpenFOAM workshop there was a paper on SIMPLE vs. Coupled, http://web.student.chalmers.se/group...SlidesOFW5.pdf

July 29, 2011, 00:41		#8
Martin Hegedus Senior Member Martin Hegedus Join Date: Feb 2011 Posts: 500 Rep Power: 19	After digging up information on rhoCentralFoam I'm uncertain it does turbulence modeling. Does rhoCentralFoam include turbulence modeling?

July 29, 2011, 08:17		#9
praveen Super Moderator Praveen. C Join Date: Mar 2009 Location: Bangalore Posts: 342 Blog Entries: 6 Rep Power: 18	rhoCentralFoam does only global time stepping. So getting convergence for steady state problems will need too many iterations. I have not looked at how well it converges, since it does not seem to calculate residuals. I am trying to implement local time stepping and run it in parallel. It does not seem to have turbulence models. It should not be difficult to add it though.

July 29, 2011, 11:14		#10
Martin Hegedus Senior Member Martin Hegedus Join Date: Feb 2011 Posts: 500 Rep Power: 19	I can't remember the details, (I tried different solvers, bcs, etc.), but for rhoCentralFoam I believe I created a code to compare the solutions at two adjacent (n and n+1) time steps to get residuals. The runs were inviscid and the grid was coarse. Anyway, unless I can find my runs, or recreate them, I should not say much.