|
[Sponsors] |
January 18, 2009, 14:32 |
Incompressible vs compressible solvers
|
#1 |
Guest
Posts: n/a
|
Hi,
I have to model an internal flow situation where the Mach number varies from 0.03 to 1.2. I have a compressible flow solver at hand. I'm wondering whether a compressible solver can solve the flow even if I have very low Mach numbers? I was told that I could re-scale my geometry so that I can have a higher Mach number and the re-scaling would a lower Re. Cheers |
|
January 18, 2009, 17:00 |
Re: Incompressible vs compressible solvers
|
#2 |
Guest
Posts: n/a
|
Not sure I understand:
If you change the geometry in the compressible solver (CS) in such a way that you change the velocity field, that would change the Mach number field. The Reynolds number has velocity and a geometry dimension in it - so Re might go up or down depending on what was changed in what direction. It might be more useful to set up the same geometry in both compressible and incompressible codes - if both codes are well-understood and checked out. Some of the older Los Alamos codes (sola-ice comes to mind) would work at low Mach numbers. Hope this is of some use to you. |
|
January 18, 2009, 20:39 |
Re: Incompressible vs compressible solvers
|
#3 |
Guest
Posts: n/a
|
The compressible flow solver would work fine at the lower mach number range if you have preconditioning implemented in the compressible solver. You rescale the wave speeds to achieve this.
|
|
January 19, 2009, 00:32 |
Re: Incompressible vs compressible solvers
|
#4 |
Guest
Posts: n/a
|
What about viscous stresses? If the solver is based on Euler equations & not Navier-Stokes, you're going to be solving for the wrong physics. Surely?
mw... www.adthermtech.com/wordpress3 |
|
January 19, 2009, 06:07 |
Re: Incompressible vs compressible solvers
|
#5 |
Guest
Posts: n/a
|
Sorry I meant rescaling the geometry and using a higher Mach numbers so that the Reynolds number still remains constant (if that makes sense). Will this be valid?
|
|
January 19, 2009, 06:15 |
Re: Incompressible vs compressible solvers
|
#6 |
Guest
Posts: n/a
|
No. For flows to be dynamically equivalent, both Reynolds and Mach number need to be the same!
|
|
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
compressible and incompressible flow | chinababu | FLUENT | 4 | November 13, 2008 06:56 |
Can a compressible solver solve incompressible ? | jinwon park | Main CFD Forum | 17 | December 13, 2007 06:00 |
Compressible -> incompressible. | Jinwon | Main CFD Forum | 6 | November 23, 2007 22:07 |
NS-incompressible and compressible flow solvers | ag | Main CFD Forum | 2 | September 27, 2005 07:18 |
Compressible vs. Incompressible formulations | Fernando Velasco Hurtado | Main CFD Forum | 3 | January 7, 2000 17:51 |