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Search took 0.00 seconds. Search: Posts Made By: vkrastev
Forum: OpenFOAM November 11, 2011, 05:00
Replies: 53
Views: 14,396
Posted By vkrastev
I know that you had problems with the shock...

I know that you had problems with the shock position also in the viscous turbulent runs, but I don't think that you should use the inviscid simulation as a comparison with the experimental data....
Forum: OpenFOAM November 8, 2011, 13:11
Replies: 53
Views: 14,396
Posted By vkrastev
Hi all, if some of you have encountered...

Hi all,
if some of you have encountered accuracy problems with rhoCentralFoam, take a look at the following tread (especially post #11)

...
Forum: OpenFOAM October 26, 2011, 05:57
Replies: 53
Views: 14,396
Posted By vkrastev
These are all interesting considerations. It...

These are all interesting considerations. It seems like the wall functions are the source of pressure fluctuations in your case, but for me it's quite hard to give a sound-logical explanation for...
Forum: OpenFOAM October 14, 2011, 10:38
Replies: 53
Views: 14,396
Posted By vkrastev
Do you mean a pressure-velocity decoupling? This...

Do you mean a pressure-velocity decoupling? This could be interesting, but honestly I can't say if it is a reasonable hypothesis...Anyway, if I understand you properly, the pressure-velocity coupling...
Forum: OpenFOAM October 13, 2011, 12:52
Replies: 53
Views: 14,396
Posted By vkrastev
I think that you have to let the simulations go...

I think that you have to let the simulations go ahead until at least the shock position becomes sufficiently stable for both models and then make some comparison. In the end your results appear not...
Forum: OpenFOAM October 13, 2011, 12:05
Replies: 53
Views: 14,396
Posted By vkrastev
No, I don't think you should change the diagonal...

No, I don't think you should change the diagonal solver options for rho, rhoU and rhoE, because as far as I have understood a little the rhoCentralFoam algorithm, these quantities are solved...
Forum: OpenFOAM October 13, 2011, 10:41
Replies: 53
Views: 14,396
Posted By vkrastev
That piece of code is missing in OF 1.7.1 (which...

That piece of code is missing in OF 1.7.1 (which is my reference version), and I really don't understand why is there in OF 2.0.0/1/x ... I think you can ignore the warning message without any...
Forum: OpenFOAM October 13, 2011, 08:33
Replies: 53
Views: 14,396
Posted By vkrastev
Just a short add-on from my side: it seems (at...

Just a short add-on from my side: it seems (at least in my internal flow case) that Tadmor's flux scheme is more stable than Kurganov's one (probably because it's slightly more dissipative, at least...
Forum: OpenFOAM October 13, 2011, 04:26
Replies: 53
Views: 14,396
Posted By vkrastev
That is my point too.

That is my point too.
Forum: OpenFOAM October 12, 2011, 12:53
Replies: 53
Views: 14,396
Posted By vkrastev
No problem, I'm interested in the performances of...

No problem, I'm interested in the performances of rhoCentralFoam too (though my case is quite different from yours).



div(tauMC) is not a convective term, but an explicitly calculated...
Forum: OpenFOAM October 12, 2011, 11:07
Replies: 53
Views: 14,396
Posted By vkrastev
If you have already tried upwind (and you did,...

If you have already tried upwind (and you did, right?), this was the most stable choice you can make about divSchemes. Why don't you try instead with a different turbulence model (for instance, the...
Forum: OpenFOAM October 12, 2011, 09:15
Replies: 53
Views: 14,396
Posted By vkrastev
Not if he is using wall functions (wall functions...

Not if he is using wall functions (wall functions work bad with too low y+ values: this is a quite basic CFD rule for wall treatment of high-Re flows).



Well, putting to zeroGradient all the...
Forum: OpenFOAM October 12, 2011, 07:42
Replies: 53
Views: 14,396
Posted By vkrastev
Well, actually I haven't played that much with...

Well, actually I haven't played that much with the waveTransmissive BC's, but the fact is that the lesser the lInf the more reflective will become the BC (in the limit of lInf=0 you'll have actually...
Forum: OpenFOAM October 12, 2011, 05:23
Replies: 53
Views: 14,396
Posted By vkrastev
No, your y+ in my opinion is ok for a wall...

No, your y+ in my opinion is ok for a wall function treatment. Instead, your boundary conditions seem not so adequate for a compressible case. I don't know if this will solve your problem, but i...
Forum: OpenFOAM October 12, 2011, 04:48
Replies: 53
Views: 14,396
Posted By vkrastev
From your fvSchemes file it is not clear if you...

From your fvSchemes file it is not clear if you are using a turbulence model or not. In addition, your mesh seems of good quality but maybe a little coarse near the wall, considering the very high...
Forum: OpenFOAM October 10, 2011, 11:16
Replies: 53
Views: 14,396
Posted By vkrastev
Well, this is quite interesting, since now I'm...

Well, this is quite interesting, since now I'm working on transonic internal flows and indeed I'm facing stability issues with the pressure based sonicFoam solver (although I'm quite sure that some...
Forum: OpenFOAM October 10, 2011, 08:56
Replies: 53
Views: 14,396
Posted By vkrastev
Hi Alberto, could you please justify this...

Hi Alberto, could you please justify this statement? To my knowledge, pressure-based solvers CAN handle transonic flows with shocks, and this has been established quite a long time ago (see for...
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