Forum: OpenFOAM Running, Solving & CFD
November 18, 2016, 07:59
|
|
Replies: 220
Views: 62,229
Elham,
What is U in your yPlus calculation...
Elham,
What is U in your yPlus calculation ? instanteneous or averaged velocity ?
Have you try to calculated utau from the averaged velocity profiles you send us ?
I mean from the mean...
|
|
Forum: OpenFOAM Running, Solving & CFD
November 10, 2016, 02:49
|
|
Replies: 220
Views: 62,229
Elham,
Well, as you can see on the forum, I...
Elham,
Well, as you can see on the forum, I ran these calculations in 2008 (with an old version of OpenFOAM) so .... I don't remember every settings.
What I remember is that if I increased the...
|
|
Forum: OpenFOAM Running, Solving & CFD
October 5, 2016, 09:20
|
|
Replies: 220
Views: 62,229
Hi Darko,
That's a weird question .... if...
Hi Darko,
That's a weird question .... if your calculation is converged (averaged field, 2nd order statistics, ...) after 10 iterations then, no need to do 100 (but it won't, I can bet on that)....
|
|
Forum: OpenFOAM Running, Solving & CFD
September 7, 2016, 03:58
|
|
Replies: 220
Views: 62,229
Dear Elham,
I don't know. OpenFoam is an...
Dear Elham,
I don't know. OpenFoam is an opensource code and usually, postProcessing tools are not that hard to understand even for beginners.
Therefore, if you have a look at the source code...
|
|
Forum: OpenFOAM Running, Solving & CFD
September 6, 2016, 02:52
|
|
Replies: 220
Views: 62,229
Dear Elham,
You should have a look at the...
Dear Elham,
You should have a look at the postChannel tool in applications/utilities/postProcessing/miscellaneous/postChannel
http://cpp.openfoam.org/v4/a04646.html
"
Post-processes data...
|
|
Forum: OpenFOAM Running, Solving & CFD
September 1, 2016, 08:57
|
|
Replies: 220
Views: 62,229
Dear Elham,
To initialize my calculation,...
Dear Elham,
To initialize my calculation, I've only used PertrubU (parabolic profile for the streamwise velocity + perturbation close to the wall on different velocity component). Note that you...
|
|
Forum: OpenFOAM Running, Solving & CFD
September 1, 2016, 03:17
|
|
Replies: 220
Views: 62,229
Dear Elham,
"I tried perturbU utility for...
Dear Elham,
"I tried perturbU utility for Retau 395 and changed the internal flow velocity at zero time but I got a small perturbation"
Yes, that is the all idea of PerturbU utility, adding...
|
|
Forum: OpenFOAM Running, Solving & CFD
June 29, 2015, 03:13
|
|
Replies: 220
Views: 62,229
Dear Canopus,
well, to calculate dudy|y=0 I...
Dear Canopus,
well, to calculate dudy|y=0 I guess your first point is y=0 U=0. The question is then where is your second points; the cell center or the face value between the 1st and the 2nd...
|
|
Forum: OpenFOAM Running, Solving & CFD
June 26, 2015, 08:00
|
|
Replies: 220
Views: 62,229
:)
as you can see it was few years ago.
...
:)
as you can see it was few years ago.
But as you proposed, I used postChannel to get Uf and then I calculated tau_w (or utau) to get y+ and u+.
It's true that your plot U=f(y) looks good...
|
|
Forum: OpenFOAM Running, Solving & CFD
June 26, 2015, 04:20
|
|
Replies: 220
Views: 62,229
Dear Canopus,
I'm sure that if you run a...
Dear Canopus,
I'm sure that if you run a calculationo from scratch (using perturbU), starting your averaging procedure at t=0 and doing only 5 cross flow it's definitly not enough.
I'm not sure...
|
|
Forum: OpenFOAM Running, Solving & CFD
June 26, 2015, 02:16
|
|
Replies: 220
Views: 62,229
Dear Canopus,
that's strange ...
Are...
Dear Canopus,
that's strange ...
Are you sure your statistics are converged. I mean how many cross-flow have you done before averaging ? you should not averaged from the begining of your...
|
|
Forum: OpenFOAM Running, Solving & CFD
June 25, 2015, 03:08
|
|
Replies: 220
Views: 62,229
Dear Canopus,
Are you sure about your...
Dear Canopus,
Are you sure about your Reynolds number ? notice that Re is not Re_tau
What are the size of you domain, velocity and viscosity ?
Could you also post your fvScheme and...
|
|
Forum: OpenFOAM Running, Solving & CFD
December 19, 2012, 04:42
|
|
Replies: 220
Views: 62,229
Dear j.t.,
I think your initial field is...
Dear j.t.,
I think your initial field is too far from reality. Uniform velocity is not enough to run a LES calculation. Even if your calculation is running, you will spend days to get converged...
|
|
Forum: OpenFOAM Running, Solving & CFD
December 18, 2012, 08:27
|
|
Replies: 220
Views: 62,229
Dear j.t.
I used a quite old version of OF...
Dear j.t.
I used a quite old version of OF for these calculations. Details of my numerics can be found on a previous message (July 30, 2008, 11:17)
I did a periodic hill calculation with the...
|
|
Forum: OpenFOAM Running, Solving & CFD
December 17, 2012, 10:23
|
|
Replies: 220
Views: 62,229
|
|
Forum: OpenFOAM Running, Solving & CFD
February 19, 2009, 12:38
|
|
Replies: 220
Views: 62,229
Hi Jianying and Ning,
I jus
Hi Jianying and Ning,
I just want to add that the reference DNS calculation we used to compare our calculation was done with a second order code (in both time and space).
So if you use (real)...
|
|
Forum: OpenFOAM Running, Solving & CFD
January 17, 2009, 13:26
|
|
Replies: 220
Views: 62,229
Hi Mou,
the weightedAverage
Hi Mou,
the weightedAverage commande calculate the volume average of a volSclalarField.
So if you have a volScalarField "toto", toto.weightedAverage(mesh.V()); gives you the average value of...
|
|
Forum: OpenFOAM Running, Solving & CFD
December 9, 2008, 09:40
|
|
Replies: 220
Views: 62,229
Hi Fabian,
Well, I used the
Hi Fabian,
Well, I used the postChannel tool to get lot's of two colums files. but after that, it's quite .... home made :o)
I'll try to clean one of these gnuplot files to do a standard...
|
|
Forum: OpenFOAM Running, Solving & CFD
December 2, 2008, 11:35
|
|
Replies: 220
Views: 62,229
Hi Philippe,
Yes, you can d
Hi Philippe,
Yes, you can do that, just telling that the shear stress in your periodic channel is compensated by the favorable pressure gradient.
So you get u_tau to get U+ and y+.
Do you...
|
|
Forum: OpenFOAM Running, Solving & CFD
December 1, 2008, 13:45
|
|
Replies: 220
Views: 62,229
Hi Philippe,
the pressure g
Hi Philippe,
the pressure gradient is calculated eatch time step from these lines (in channelOodles.C):
// Extract the velocity in the flow direction
dimensionedScalar magUbarStar...
|
|
Forum: OpenFOAM Running, Solving & CFD
August 29, 2008, 03:39
|
|
Replies: 220
Views: 62,229
Hi LES FOAMers
Sorry for th
Hi LES FOAMers
Sorry for the delay but, the august month is very quiet and vacation was there ..... well, I came back :-)
I'm running 3 jobs now with the same mesh :
- static oneEqEddy ...
|
|
Forum: OpenFOAM Running, Solving & CFD
July 30, 2008, 07:57
|
|
Replies: 220
Views: 62,229
@Eugene Thank you for you com
@Eugene Thank you for you comment, I'll try that.
I thought about that point before and that is the reason why I'm doing a calculation with the dynamic procedure. I'm not supposed to need Van...
|
|
Forum: OpenFOAM Running, Solving & CFD
July 30, 2008, 05:55
|
|
Replies: 220
Views: 62,229
@Luca: I don't agree with you,
@Luca: I don't agree with you, I think for both Umean and rms I underpredicted the value. In the rms, I overpredicted the pic of rms and, the maximum is shift to bigger y+ .... which is not good...
|
|
Forum: OpenFOAM Running, Solving & CFD
July 30, 2008, 05:17
|
|
Replies: 220
Views: 62,229
Hi Eugene,
euh ....not real
Hi Eugene,
euh ....not really :o)
As I told, the geometry and the grid are different. it's the same geometry as the DNS calculation. So streaks are shorter than the box and there is (should...
|
|
Forum: OpenFOAM Running, Solving & CFD
July 30, 2008, 03:07
|
|
Replies: 220
Views: 62,229
Thank you for your answers,
Thank you for your answers,
@Luca : the only difference between Uf_0 and Uf_2 is the mesh repartition normal to the wall. one is linear and the other is a tanh. But, because in the plots only...
|
