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-   -   Multiphase flow in cavity---B.C. doesn't correspond to physical meaning (https://www.cfd-online.com/Forums/openfoam-pre-processing/181335-multiphase-flow-cavity-b-c-doesnt-correspond-physical-meaning.html)

linyanx December 12, 2016 15:02

Multiphase flow in cavity---B.C. doesn't correspond to physical meaning
 
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Dear OpenFOAMers,

I have one question regarding the B.C setting while using 'interFoam' solver.

I created one cavity for 2D simulation with left, right, top, lower walls are all set as 'type wall'. I hope 'no-slip' condition would work in this boundary setting. Therefore, I set the velocity at left, right, top, lower walls as 'type fixed value' in '0/U' file and set pressure as zeroGradient in '0/p_rgh'. The simulation does work, however, according to the animation of the result. I think it totally lost the physical meaning. Because I found the fluid at the wall will move up and down with time and this absolutely violated the physical meaning of 'type wall' which means 'no-slip' at the wall.
:confused::confused::confused:
Does someone have any comment on this problem? Any correction is highly appreciated!!!

Thanks in advance,

Linyan

linyanx December 13, 2016 16:11

After changing the left and right's B.C. into 'cyclic'. The motion of the fluid keep steady on the wall. And that is the desired motion for the gravity wave. However, it still didn't make sense that the boundary type 'wall' would not work. A little bit confused about that.:confused::confused:

Linyan

linyanx December 14, 2016 17:17

Solved
 
The problem was solved.

The reason credits to my ignorance of the 'wall' effect. Initially, I didn't believe the openfoam's result for the gravity wave period time doesn't follow my theoretical calculation.

However, then the fault was caused by ignorance of the 'wall' effect. If the model has the wall, the behavior of the wave will be affected by the reflection of gravity wave by the wall(additionally).

That is the reason for simulation with 'type wall' didn't follow my calculation. While at the same time, it did work under the B.C. 'type cyclic'.

Linyan


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