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Search took 0.00 seconds. Search: Posts Made By: Elham
Forum: OpenFOAM Running, Solving & CFD March 20, 2017, 22:20
Replies: 220
Views: 62,301
Posted By Elham
Hi everyone, I have a turbulent flow in a...

Hi everyone,

I have a turbulent flow in a channel. The channel is 0.3*0.05*0.075m. When I add a stationary 2mm diameter sphere in the domain the turbulent gets laminar quickly. The sphere BC is...
Forum: OpenFOAM Running, Solving & CFD January 7, 2017, 02:46
Replies: 220
Views: 62,301
Posted By Elham
You can try using...

You can try using turbulentIntensityKineticEnergyInlet BC for k and see what will happen. Please let me know if it works.
Forum: OpenFOAM Running, Solving & CFD January 4, 2017, 22:28
Replies: 220
Views: 62,301
Posted By Elham
How big is the Re number? Is it in the turbulent...

How big is the Re number? Is it in the turbulent limit?
Forum: OpenFOAM Running, Solving & CFD January 4, 2017, 07:31
Replies: 220
Views: 62,301
Posted By Elham
I don't know if the setAverage does push the...

I don't know if the setAverage does push the pressure difference like fvOption. Why you did not use fvOption in this case?
Forum: OpenFOAM Running, Solving & CFD January 2, 2017, 22:25
Replies: 220
Views: 62,301
Posted By Elham
Happy new year too. It is quite laminar. The...

Happy new year too.
It is quite laminar. The problem is not the number of flow throughs. You may missed something in the BCs definition. All of BCs except the walls has to be cyclic and fvOptionDict...
Forum: OpenFOAM Running, Solving & CFD January 2, 2017, 22:22
Replies: 220
Views: 62,301
Posted By Elham
Which solver are you using? Do you have a kind of...

Which solver are you using? Do you have a kind of source term to push the pressure difference or a cyclic BC. I myself have lots of problem for producing turbulent flow in the channel while the...
Forum: OpenFOAM Running, Solving & CFD December 30, 2016, 02:59
Replies: 220
Views: 62,301
Posted By Elham
Would you please send the velocity contour after...

Would you please send the velocity contour after 200 flow through?
Forum: OpenFOAM Running, Solving & CFD December 28, 2016, 21:39
Replies: 220
Views: 62,301
Posted By Elham
Is the fvOption dictionary in your system...

Is the fvOption dictionary in your system directory and active? It forces the pressure difference through the channel. All of the boundary conditions should be cyclic as well.
Forum: OpenFOAM Running, Solving & CFD December 27, 2016, 06:44
Replies: 220
Views: 62,301
Posted By Elham
Can you see any perturbation after using perturbU...

Can you see any perturbation after using perturbU utility? Any small perturbation is enough. Then you need to have enough time to get turbulent.
Forum: OpenFOAM Running, Solving & CFD December 6, 2016, 02:44
Replies: 220
Views: 62,301
Posted By Elham
I finally could get rid of the scale difference...

I finally could get rid of the scale difference from my results and DNS ones in wall coordinate by calculating u_tau as following:

u_tau=sqrt(wallShearStressLES)

and wallShearStressLES is a...
Forum: OpenFOAM Running, Solving & CFD November 21, 2016, 20:27
Replies: 220
Views: 62,301
Posted By Elham
Dear all, I am wondering in yPlus...

Dear all,

I am wondering in yPlus calculation if it is correct to have the gradient of U, mag(snGrad(U))? or it must be something like mag(snGrad(flowDirection & U)))? Although I have tested it...
Forum: OpenFOAM Running, Solving & CFD November 20, 2016, 21:48
Replies: 220
Views: 62,301
Posted By Elham
I suppose U in yPlus is instantaneous but I use...

I suppose U in yPlus is instantaneous but I use the time averaged one for calculating utau.
How can I have tauw from mean velocity?
Forum: OpenFOAM Running, Solving & CFD November 20, 2016, 21:01
Replies: 220
Views: 62,301
Posted By Elham
Dear Timofey, When I use fieldAverage to have...

Dear Timofey,
When I use fieldAverage to have UMean in each outputTime, I just have UMean in the outputTime directory. So I need to keep output time directory which is demands big memory space.
Forum: OpenFOAM Running, Solving & CFD November 18, 2016, 02:43
Replies: 220
Views: 62,301
Posted By Elham
Dear Mahdi, I calculated utau by means of...

Dear Mahdi,

I calculated utau by means of wallGradU and wallShearStress utility but the big gap between mine and DNS exists. Actually, the utau in all of the methods are nearly the same. You can...
Forum: OpenFOAM Running, Solving & CFD November 14, 2016, 03:09
Replies: 220
Views: 62,301
Posted By Elham
my case and DNS result are so different

Dear all,

My results for Re_tau=330, target Re_tau=395, with 5 cells in y+<5 and the first y+=0.73 and Re_b=13350 has been attached. As you see the profile in global coordinate is near to DNS...
Forum: OpenFOAM Running, Solving & CFD November 10, 2016, 20:42
Replies: 220
Views: 62,301
Posted By Elham
Thanks. Elham

Thanks.

Elham
Forum: OpenFOAM Running, Solving & CFD November 9, 2016, 21:41
Replies: 220
Views: 62,301
Posted By Elham
Co number effect

Dear Cedric,

Would you please let me know why you kept Co number less than 0.4? Is it based on your own experience and cause better results?
I had a relatively good results with rough mesh but...
Forum: OpenFOAM Running, Solving & CFD October 31, 2016, 20:30
Replies: 220
Views: 62,301
Posted By Elham
Dear Timofe, The star data are the DNS ones....

Dear Timofe,

The star data are the DNS ones. Sorry I forgot to mention that. The jiggling may be because of the lack of enough points of probe.

Thanks for all your helps.

Cheers,

Elham
Forum: OpenFOAM Running, Solving & CFD October 31, 2016, 02:36
Replies: 220
Views: 62,301
Posted By Elham
My global coordinate plot

Dear Timofey,

By reading your report carefully, I understood that your Uc which is the centre line velocity is very near to mine, let's say, 0.1497 comparing to yours 0.15210, consequently our...
Forum: OpenFOAM Running, Solving & CFD October 27, 2016, 22:17
Replies: 220
Views: 62,301
Posted By Elham
Cannot get to Timofey results

Dear Timofey,

Since I couldn't get to my desired Retau with a very small channel area, I run the channel that you have used with all your settings including the channel size, mesh, solvers,... ...
Forum: OpenFOAM Running, Solving & CFD October 18, 2016, 02:24
Replies: 220
Views: 62,301
Posted By Elham
better convergence in final residulas

Dear all,

I have checked the log file and I knew that the final residuals for Ux, Uy, Uz , k and p are much better. The ones that I've reported in the last post were initial residuals. The final...
Forum: OpenFOAM Running, Solving & CFD October 17, 2016, 21:52
Replies: 220
Views: 62,301
Posted By Elham
convergence problem in LES modeling of turbulent channel flow

Dear Timofey,

Since I had convergence problem I mean Ux and Uy residuals were around 0.1, Ux and k were 0.01, p was 0.3 although cumulative and global residuals were O(e-8) I have put all of...
Forum: OpenFOAM Running, Solving & CFD October 7, 2016, 01:23
Replies: 220
Views: 62,301
Posted By Elham
exact values of velocity for each cell center

Dear all,

I am going to plot uPlus versus yPlus and I want to determine if the number of cells in laminar sublayer when yPlus is less than one is enough. How can I have the exact values of...
Forum: OpenFOAM Running, Solving & CFD September 21, 2016, 02:23
Replies: 220
Views: 62,301
Posted By Elham
Time-averaged velocity profile versus instantaneous one

Hello guys,

Is instantaneous velocity profile, in turbulent region, much different from time-averaged one? I mean is it possible that the time averaged profile looks like a fully developed channel...
Forum: OpenFOAM Running, Solving & CFD September 15, 2016, 21:59
Replies: 220
Views: 62,301
Posted By Elham
Dear Siavash, It would be your kindness if...

Dear Siavash,

It would be your kindness if you send it to my email or attach here. My email address is elham.mohammadi@postgrad.curtin.edu.au.
I let my modified channel395 case to be run. After...
Showing results 1 to 25 of 40
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