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June 24, 2008, 12:14
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Maybe a dumb question but... H
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Senior Member
John Deas
Join Date: Mar 2009
Posts: 160
Rep Power: 6  |
Maybe a dumb question but... How is it that Fluent is capable of fully-implicit time discretisation while OpenFOAM is not ?
Or, if put another way, what would be required to have fully-implicit time discretisation in OF ? |
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June 24, 2008, 12:39
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What do you mean by "fully imp
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Senior Member
Eugene de Villiers
Join Date: Mar 2009
Posts: 723
Rep Power: 10 |
What do you mean by "fully implicit" time discretization, and why do you think there is a difference between Fluent and OpenFOAM in this regard?
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June 24, 2008, 12:46
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You would need to solve the eq
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Senior Member
Billy
Join Date: Mar 2009
Posts: 167
Rep Power: 6 |
You would need to solve the equations of mass, momentum and energy simultaneously instead of segregated.
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June 24, 2008, 12:49
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For example, you won't have li
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Senior Member
John Deas
Join Date: Mar 2009
Posts: 160
Rep Power: 6 |
For example, you won't have limitation on your Courant Number in Fluent.
This question arised as the Courant number can be a limitating factor and force you to have timesteps smaller than the one required by the eddy dissipation time. |
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June 24, 2008, 13:11
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Most of the time schemes in Op
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#5 |
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Senior Member
Eugene de Villiers
Join Date: Mar 2009
Posts: 723
Rep Power: 10 |
Most of the time schemes in OpenFOAM are "fully implicit". There are probably other things that Fluent does to run stable at very high CFL numbers.
On the other hand I regularly run LES with maximum CFL numbers of 2-3 without problems. It depends on the solver and your limiters I guess. |
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June 24, 2008, 13:50
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Sorry Eugene - time to read a
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#6 |
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Senior Member
Hrvoje Jasak
Join Date: Mar 2009
Location: London, England
Posts: 1,695
Rep Power: 17 |
Sorry Eugene - time to read a book. The guy is talking about a block solution of the compressible flow system, which is "more implicit" than the segregated solution you are used to.
This is coming with my new block matrix implementation. Hrv
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Hrvoje Jasak |
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June 24, 2008, 13:59
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Hrv,
"This is coming with my
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#7 |
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Senior Member
Xiaofeng Liu
Join Date: Mar 2009
Location: San Antonio, TX, USA
Posts: 117
Rep Power: 6 |
Hrv,
"This is coming with my new block matrix implementation" When? I have been looking forward for this for a long time.
__________________
Xiaofeng Liu, Assistant Professor Department of Civil and Environmental Engineering University of Texas at San Antonio email: xiaofeng.liu@utsa.edu Web: http://engineering.utsa.edu/~xiaofengliu |
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June 24, 2008, 14:37
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As you may have guessed, it is
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#8 |
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Senior Member
Hrvoje Jasak
Join Date: Mar 2009
Location: London, England
Posts: 1,695
Rep Power: 17 |
As you may have guessed, it is all about funding: fully financed projects get priority, deadlines etc, meaning that interesting pieces of work get delayed.
It has been delayed for an inexcusable number of times, but it will make you happy to know that some people are already running block-coupled solutions. Apologies for the delay, Hrv
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Hrvoje Jasak |
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June 24, 2008, 14:46
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We should thank you for develo
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Senior Member
Billy
Join Date: Mar 2009
Posts: 167
Rep Power: 6 |
We should thank you for developing such a great software!
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June 24, 2008, 18:23
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Great! Hrv
I should also th
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Senior Member
Xiaofeng Liu
Join Date: Mar 2009
Location: San Antonio, TX, USA
Posts: 117
Rep Power: 6 |
Great! Hrv
I should also thank you for sharing.
__________________
Xiaofeng Liu, Assistant Professor Department of Civil and Environmental Engineering University of Texas at San Antonio email: xiaofeng.liu@utsa.edu Web: http://engineering.utsa.edu/~xiaofengliu |
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June 25, 2008, 08:40
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Dear Hrv
I wondered if the
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#11 |
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Member
Patricio Bohorquez
Join Date: Mar 2009
Location: Jaén, Spain
Posts: 81
Rep Power: 6 |
Dear Hrv
I wondered if the community can enjoy such piece of work via the development version? This would be thankful news (among others). Best wishes Patricio |
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