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Segregated Solver, Segregated group

Posted Feb 20, 2013, 1:14 a.m. EST Fluid & Heat, Interfacing, Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD), Geometry, Installation & License Management, Materials, Mesh, Modeling Tools & Definitions, Parameters, Variables, & Functions, Results & Visualization, Studies & Solvers Version 4.3a 2 Replies

Nithin
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What is the meaning of "Segregated Solver" and "Segregated Group"?

While computing for the results, I am getting a line like follows... "Segregated Solver 17% Step 3" .
And the value beside Step in that line is varying between 1, 2 & 3.

Does the step in that line mean "time step"?
As i have a time step of 300 sec spanning from 0 sec to 86400 sec, total 288 step.
So, will need to go through 288 steps??
2 Replies Last Post Feb 20, 2013, 4:53 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 20, 2013, 1:56 a.m. EST
Hi

check the doc on the solver. When COMSOL tries to solve a complex multi-physics problem, it can either solve it directly (all variables at a time, or try a segregated group approach (uses less ram but takes longer) by solving (in a loop) for some variables, then using the results to solve for the others. This approach is often better for highly non-linear models too

--
Good luck
Ivar
Hi check the doc on the solver. When COMSOL tries to solve a complex multi-physics problem, it can either solve it directly (all variables at a time, or try a segregated group approach (uses less ram but takes longer) by solving (in a loop) for some variables, then using the results to solve for the others. This approach is often better for highly non-linear models too -- Good luck Ivar
Mattia Montanari
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Posted: 1 decade ago Feb 20, 2013, 4:53 a.m. EST
Hello,

" Does the step in that line mean "time step"?"
No.
the value Step =[1,2,3] is due to the termination technique you have chosent. it has nothing about time step.
You find more here
model-> study1->Solver config->solver1->time-Depend -> segregated step -> "method and termination"

"So, will need to go through 288 steps??"
No.
Many more. Comsol gives you 288 results (in time for instance), but actually it solves the linear(ized) system many times more!
You find more here
model-> study1->Solver config->solver1->time-Depend ->"output" try to set the "time to store" == 'steps taken by solver'

As Ivar suggested: go through the manual :-)

Hope it helps,
Mattia
Hello, " Does the step in that line mean "time step"?" No. the value Step =[1,2,3] is due to the termination technique you have chosent. it has nothing about time step. You find more here model-> study1->Solver config->solver1->time-Depend -> segregated step -> "method and termination" "So, will need to go through 288 steps??" No. Many more. Comsol gives you 288 results (in time for instance), but actually it solves the linear(ized) system many times more! You find more here model-> study1->Solver config->solver1->time-Depend ->"output" try to set the "time to store" == 'steps taken by solver' As Ivar suggested: go through the manual :-) Hope it helps, Mattia

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