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Running the simulation for the required time span in more than one times (loops)

Posted Feb 28, 2013, 12:07 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 3 Replies

Nithin Kumar Peratla
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Dear sir,

My requirement is "Running the simulation for the required time span in more than one times (loops)".

I actually do not know the initial values of temperatures of the room that I am going to analyse on CFD. So, I wish to run it for more that one times (or you can say loops) so as to stabilise my results and compare them with the real world ones. Is it possible and how should I do it??
3 Replies Last Post Feb 28, 2013, 8:24 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 28, 2013, 1:22 a.m. EST
Hi

You could try a stationary solver first, to get coherent initial values, and then run a time dependent series starting from the previous results (used as initial conditions) like this you know how you start.

in case you have formulas including "t" in your BCs, add a Global Definition Parameter t = 0[s] to your model, this defines also t=0 for your stationary solver, but COMSOL will adapt "t" to the right values during the time dependent solving sequence

--
Good luck
Ivar
Hi You could try a stationary solver first, to get coherent initial values, and then run a time dependent series starting from the previous results (used as initial conditions) like this you know how you start. in case you have formulas including "t" in your BCs, add a Global Definition Parameter t = 0[s] to your model, this defines also t=0 for your stationary solver, but COMSOL will adapt "t" to the right values during the time dependent solving sequence -- Good luck Ivar
Nithin Kumar Peratla
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Posted: 1 decade ago Feb 28, 2013, 4:53 a.m. EST
Sir,

Thank you for your patience in answering my queries...

I am having the results for 1st day (24 hours) and I wish to use the output of the 1st day as initial values for 2nd day (24-48 hrs). What I mean through this is that, I have different temperature conditions for two different consecutive days of my analysis. So, Is there any way for doing this?
Sir, Thank you for your patience in answering my queries... I am having the results for 1st day (24 hours) and I wish to use the output of the 1st day as initial values for 2nd day (24-48 hrs). What I mean through this is that, I have different temperature conditions for two different consecutive days of my analysis. So, Is there any way for doing this?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Feb 28, 2013, 8:24 a.m. EST
Hi

you can call the initial conditions, either from the "initial value node" or rfom a previous calculated study, this is set in the solver node, in one of the sub-tabs, "variables solved for"

--
Good luck
Ivar
Hi you can call the initial conditions, either from the "initial value node" or rfom a previous calculated study, this is set in the solver node, in one of the sub-tabs, "variables solved for" -- Good luck Ivar

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