Forum: CFX
June 20, 2018, 01:41
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Replies: 34
Views: 4,772
Dear Glenn,
I have let the default settings...
Dear Glenn,
I have let the default settings of CFX-Pre and did not change any of them.
1) What do you recommend for any of these:
Advection scheme, Transient Scheme and Turbulence numerical?...
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Forum: CFX
June 19, 2018, 06:47
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Replies: 34
Views: 4,772
Dear Glenn,
All the settings I have made is...
Dear Glenn,
All the settings I have made is like the attached picture, Is there any thing wrong with this?
I checked my linear Solution which is dependent to conservation target and I used its...
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Forum: CFX
June 19, 2018, 04:09
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Replies: 34
Views: 4,772
look at this attached picture;
In the 6th...
look at this attached picture;
In the 6th iteration, the residuals are under 1e-4 which is the desired convergence criteria. But the solution does not end at this time step and continues all 10...
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Forum: CFX
June 19, 2018, 03:07
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Replies: 34
Views: 4,772
Dear Glenn,
2a) Do you mean that I should...
Dear Glenn,
2a) Do you mean that I should start Time averaging after running my case for some transient time steps? So that I pass the initial time steps?
I feel I still have some problems with...
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Forum: CFX
June 18, 2018, 16:22
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Replies: 34
Views: 4,772
Dear Glenn,
Thanks for your complete and fast...
Dear Glenn,
Thanks for your complete and fast answer.
1) Yes, since I have seen other papers pointed to the TKE over-prediction and my model is somehow difference (such as drag and lift models)...
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Forum: CFX
June 17, 2018, 08:07
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Replies: 34
Views: 4,772
Dear Glenn,
1) I'm using k-epsilon model. As...
Dear Glenn,
1) I'm using k-epsilon model. As other papers have reported, this model over-predicts TKE. And some other papers that have compared experimental TKE with numerical TKE(using k-epsilon...
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Forum: CFX
June 16, 2018, 06:12
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Replies: 34
Views: 4,772
Dear Glenn
This is my grid quality:
Minimum...
Dear Glenn
This is my grid quality:
Minimum Orthogonal Quality = 7.09228e-01
(Orthogonal Quality ranges from 0 to 1, where values close to 0 correspond to low quality.)
Maximum Ortho Skew = ...
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Forum: CFX
June 16, 2018, 05:47
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Replies: 34
Views: 4,772
Dear Glenn,
a) Actually In my case which is a...
Dear Glenn,
a) Actually In my case which is a two phase bubble column, finer grid causes errors and we would like to use a larger grid in order to eliminate turbulence modes. So I don't want to...
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Forum: CFX
June 15, 2018, 08:35
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Replies: 34
Views: 4,772
Dear Glenn,
1) Actually I though that...
Dear Glenn,
1) Actually I though that whether I start from 1e-6 and increase the time step or start from 0.05 and decrease it, I will obtain the same time step. but it is not true.
Actually I set...
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Forum: CFX
June 15, 2018, 07:57
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Replies: 34
Views: 4,772
Dear Glenn,
I used
Total Time = 20[s] ...
Dear Glenn,
I used
Total Time = 20[s]
First update = 0[s]
Time step update freq = 1
Initial Time step = 0.05[s]
Maximum timestep = 0.05 [s]
Minimum time step = 1e-7[s]
target max = 5
target...
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Forum: CFX
June 15, 2018, 07:14
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Replies: 34
Views: 4,772
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Forum: CFX
June 15, 2018, 07:11
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Replies: 34
Views: 4,772
Dear Glenn
thanks for your answer,
2) for...
Dear Glenn
thanks for your answer,
2) for my second question I didn't know that convergence criteria needs to be studied as well as time step and grid. So I need to study tighter convergence...
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Forum: CFX
June 15, 2018, 06:04
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Replies: 34
Views: 4,772
Dear Glenn,
1) As I can see the RMS residuals...
Dear Glenn,
1) As I can see the RMS residuals are now under 1e-4. I sent a picture in my last quote. and you can see its below 1E-4 which is my residual target.
2) About the convergence criteria...
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Forum: CFX
June 15, 2018, 03:21
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Replies: 34
Views: 4,772
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Forum: CFX
June 15, 2018, 03:00
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Replies: 34
Views: 4,772
Dear Erik
Thanks for your answer, but for me I...
Dear Erik
Thanks for your answer, but for me I need to know more about how it works. only reading 2 lines about it is not enough for me because those 2 lines of explanation are guessable by only...
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Forum: CFX
June 14, 2018, 05:05
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Replies: 34
Views: 4,772
Dear Glenn,
Yes it is a transient solution....
Dear Glenn,
Yes it is a transient solution. First I ran a steady solution and used it as my initial guess. The image that I attached is transient RMS plot, since this problem is completely unsteady...
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Forum: CFX
June 13, 2018, 11:51
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Replies: 34
Views: 4,772
Dear Glenn,
Thank you so mush, cause I was...
Dear Glenn,
Thank you so mush, cause I was really worried about the settings and you really advised me helpfully.
only I just want to ask my last questions:
1) the residual RMS plot that I get for...
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Forum: CFX
June 13, 2018, 06:41
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Replies: 34
Views: 4,772
Dear Glenn,
1) Does it mean that my settings...
Dear Glenn,
1) Does it mean that my settings are all right and it has nothing to do with divergence? I attached the .out file too. Did you check that as well?
2) By the way, How can I check...
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Forum: CFX
June 13, 2018, 03:52
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Replies: 34
Views: 4,772
Error code 255
Hello everyone
I'm modelling a bubble column. during time independence study, when I decreased the time step from 0.05 to 0.025, after about 3 days of simulation, my run has stopped with the below...
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