Buoyancy driven flow
Hi everybody,
I'm going to solve a simple flow over flat plate and I'm going to have heat equation and buoyancy effects in my flow. My domain size is 1500(height)x6000x6000 [m] and my first grid center is located 0.03 away from the ground. I have periodic lateral BC, Symmetry top BC and no-slip wall BC. I can simulate the flow when I have a neutral case but with temperature it diverges very fast. Do you have any idea what could be wrong? Note that with this size Grashof number becomes enormous, but I don't know if that's the problem. I appreciate all your suggestions :) |
How about first trying with reducing your URF and making your solution more stable.
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it sounds like a grid problem. Especially with buoyancy driven flow. Most of the interaction will be close to the wall, so you need a good grid in that region. I am assuming your plate is vertical and not horizontal.
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maybe, it can be a case of numerical instability due to the high Gr number...
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Now, even the temperature equation works fine but only if I disregard the gravitation. |
I might also take a look at the block communications (it's a multi-block structured code I'm using) to see if something goes strange ...
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problem partly solved, not sure if it's true ...
Hi again,
regarding the issue with buoyancy driven flow, I tried to decouple temperature and momentum equations completely i.e. after the solution for pressure and velocities converge, I solve the heat equation and most importantly "add the buoyancy contributions". Seems it solved the issue ... I know it's a general practice to treat the heat equation like this (quasi-steady) but not sure if it's true when you have buoyancy? since buoyant force affects the flow field directly and might make it inaccurate ... |
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show me by CFX
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My problem is the same as yours. I have fluid flow with heat transfer and the buoyancy takes place through my model. Regards |
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thanks for your good thread.However, I'm still sad because I asked to show me how until I do it after 2 months!!:mad:..some guys do not care about the others. you will feel better whan youbecome helpful member:cool: |
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