what is the importance of deltaT and endTime entries in system/solid/controlDict?

amuzeshi · February 9, 2020, 12:48

Honored solidFoamers,
I am a little bit confused about the solids4Foam algorithm during an FSI simulation. The main question is what is the importance of deltaT and endTime entries in system/solid/controlDict ?

My understanding is as follows:
1- Fluid is solved in the current timeStep (specified in system/controlDict.deltaT).
2- Forces are applied on the solid and the displacement is calculated for THIS TIMESTEP, but WHICH TIMESTEP? The one that is specified in system/controlDict or the other one in system/solid/controlDict?
3- ...
...
This question can be asked in another way:
In an FSI simulation, is it not enough to solve fluid in a transient manner and solve solid in a steady manner at the same time step? If solids4Foam does so, why, for example in elastic beam tutorial, d2dt2Scheme is specified as Euler and not steadyState ?

Kind Regards,
Ali

Hgholami · February 11, 2020, 01:00

Dear Ali
As I know, the timeStep must be same in fluid and solid solver. So it called from system/controlDict. You can delete solid/controlDict and run simulation.

February 9, 2020, 12:48	what is the importance of deltaT and endTime entries in system/solid/controlDict?	#1
amuzeshi Senior Member Ali Shayegh Join Date: Oct 2015 Posts: 130 Rep Power: 10	Honored solidFoamers, I am a little bit confused about the solids4Foam algorithm during an FSI simulation. The main question is what is the importance of deltaT and endTime entries in system/solid/controlDict ? My understanding is as follows: 1- Fluid is solved in the current timeStep (specified in system/controlDict.deltaT). 2- Forces are applied on the solid and the displacement is calculated for THIS TIMESTEP, but WHICH TIMESTEP? The one that is specified in system/controlDict or the other one in system/solid/controlDict? 3- ... ... This question can be asked in another way: In an FSI simulation, is it not enough to solve fluid in a transient manner and solve solid in a steady manner at the same time step? If solids4Foam does so, why, for example in elastic beam tutorial, d2dt2Scheme is specified as Euler and not steadyState ? Kind Regards, Ali

February 11, 2020, 01:00		#2
Hgholami Senior Member Hojatollah Gholami Join Date: Jan 2019 Posts: 171 Rep Power: 7	Dear Ali As I know, the timeStep must be same in fluid and solid solver. So it called from system/controlDict. You can delete solid/controlDict and run simulation. amuzeshi likes this. Last edited by Hgholami; February 11, 2020 at 01:57. Reason: detail

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