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Is it normal for an unsteady simulation to appear steady initially? |
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November 27, 2020, 13:02 |
Is it normal for an unsteady simulation to appear steady initially?
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#1 |
New Member
Bradley Craig
Join Date: Oct 2020
Posts: 13
Rep Power: 6 |
As the title says.
I am running a 2D turbulent, unsteady simulation of a simple cylinder as a test case using a 2nd order dual time stepping method and after a large number of iterations in the problem doesnt seem to be dispaying any unsteady flow characteristics. Is this transient behaviour to be expected initially? Thanks in advance |
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November 28, 2020, 12:20 |
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#2 |
Senior Member
Pedro Gomes
Join Date: Dec 2017
Posts: 466
Rep Power: 14 |
What unsteady phenomena are you expecting to capture?
You will not see turbulence eddies with a URANS simulation... Another possibility is that your timestep is too large for what you are simulating (vortex shedding?) and so everything get's damped. |
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November 28, 2020, 14:33 |
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#3 |
New Member
Bradley Craig
Join Date: Oct 2020
Posts: 13
Rep Power: 6 |
I was expecting to see vortex shredding, but instead i just obtain a fully developed, constant wake behind the cylinder.
I will try decreasing the timestep to see if this will show signs of vortexes. Thank you |
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Tags |
cylinder, structured mesh., unsteady flow, urans |
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