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May 1, 2015, 13:49 |
No. of Iterations per Timestep
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#1 |
Member
Join Date: Nov 2014
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I am running LES unsteady simulations and I want a time-series solution.
For a given timestep, I want to have an accurate intepretation of the evolution. My problem is that I dunno how many iterations I should run per time step? What do I need to judge and what parameters should I check/limit? Appreciate all help please. |
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May 2, 2015, 14:39 |
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#2 |
New Member
Tim Meier
Join Date: Mar 2015
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It is very important to ensure the convergence within each time step. Create some monitor points in your domain near "busy" locations (e.g. inside jets, at separation points, ...) and check the convergence of the pressure.
The pressure convergence can be checked with a plot (pressure on the y-axis and the number of iterations on the x-axis). Now you can adjust the number of inner iterations in order to get a "constant" converged pressure value within a time step. |
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May 2, 2015, 15:04 |
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#3 | |
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Quote:
Im using StarCCM to run my simulations. Within it, the default residual plot monitors the residues of x,y,z momentum and continuity. My problem involves flow separation over a bluff body. So im guessing i should place a probe at the shear layer and monitor the pressure for convergence. But is there any smart way to select the point or I just have to choose? typically, how many inner iterations are required? im running 20 per timestep now. Why 20? i just picked a number cos I read somewhere that for smaller global timestep, the number of inner iterations can be small. |
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May 3, 2015, 06:35 |
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#4 | |
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shahrooz
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May 4, 2015, 02:44 |
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#5 |
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Vukosi
Join Date: May 2015
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I am quite new to CFD and the forum so pardon my "inappropriateness" if any exists. I am running a simulation and a set it on 1500 simulation but the solution completes before the iterations are complete, i.e at 600 iterations. What is the meaning of that? Does it mean that the solution has converged?
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May 4, 2015, 02:51 |
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#6 | |
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shahrooz
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May 4, 2015, 03:16 |
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#7 | |
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