substitute for moving meshes

Thangam · March 31, 2015, 09:31

If one has to simulate oscillating plate/solid wall ( sinusoidal function of time) in a domain (a simple piston movement in 'y' direction), the obvious way would be scenario 1. For brevity, assume there is no topological changes involved.

Scenario 1:
To use dynamic mesh (the dynamicFvMesh class) and move the mesh points via the prescribed equation.

solver: pimpleDyMFoam, dynamicInkJet etc.(almost all the dynamic solvers)

Scenario 2:
The fluid near wall takes up a zero velocity (assuming no slip). Now, With this in mind, using an oscillatingFixedValue boundary condition in 'U' at the plate/solid wall (working out the velocity of the fluid for the plate's displacement amplitude) as the fluid should obey the no slip condition and produce the flow features similar to a moving mesh ?

Will the result of scenario 2 be different to scenario 1? Is scenario 2 the right way to represent a near wall fluid with no slip? what happens to 'k' and 'pressure' in scenario 2?

solver: pimpleFoam should suffice?

Thanks
Thangam.

Bodo1993 · May 4, 2021, 18:01

Hi, I am wondering about a similar problem. The solver I use does not incorporate the dynamic meshing library. The case involves the removal of a solid wall (with thickness t) from the fluid 2D domain.
I would appreciate it if you can advise on the second scenario settings (fixing the solid wall and moving the fluid instead).

Thank you in advance.

March 31, 2015, 09:31	substitute for moving meshes	#1
Thangam Member Thangam Natarajan Join Date: Dec 2010 Location: Perth Posts: 70 Rep Power: 17	If one has to simulate oscillating plate/solid wall ( sinusoidal function of time) in a domain (a simple piston movement in 'y' direction), the obvious way would be scenario 1. For brevity, assume there is no topological changes involved. Scenario 1: To use dynamic mesh (the dynamicFvMesh class) and move the mesh points via the prescribed equation. solver: pimpleDyMFoam, dynamicInkJet etc.(almost all the dynamic solvers) Scenario 2: The fluid near wall takes up a zero velocity (assuming no slip). Now, With this in mind, using an oscillatingFixedValue boundary condition in 'U' at the plate/solid wall (working out the velocity of the fluid for the plate's displacement amplitude) as the fluid should obey the no slip condition and produce the flow features similar to a moving mesh ? Will the result of scenario 2 be different to scenario 1? Is scenario 2 the right way to represent a near wall fluid with no slip? what happens to 'k' and 'pressure' in scenario 2? solver: pimpleFoam should suffice? Thanks Thangam.

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May 4, 2021, 18:01		#2
Bodo1993 Senior Member Join Date: Jul 2019 Posts: 148 Rep Power: 7	Hi, I am wondering about a similar problem. The solver I use does not incorporate the dynamic meshing library. The case involves the removal of a solid wall (with thickness t) from the fluid 2D domain. I would appreciate it if you can advise on the second scenario settings (fixing the solid wall and moving the fluid instead). Thank you in advance.