September 19, 2022 at 2:02 amMr Eri MMSubscriberHello everyone,I have a problem with flow between fixed parallel plates. On the top plate I have a no-slip condition. But on the bottom plate, I have a boundary condition where the velocity is non-zero. How can I add the boundary condition on the bottom plate? Would it be through a UDF? Looking through Fluent, I couldn't see an option in the wall tab.
September 19, 2022 at 8:43 americ1234598765Subscriber
What's the boudnary type of the bottom plate? If it is a interface, then choosing couple option in the mesh interface setting in Fluent could treat that boudnary as impermeable wall.
Otherwise, it is strange that Fluent can not set a no slip condition on a wall boudnary.
September 19, 2022 at 9:58 amDrAmineAnsys Employee
On the bottom wall: what do you know? Do you know the velocity of the wall? Does the fuild stick to that moving wall?
September 19, 2022 at 4:26 pmMr Eri MMSubscriber
Hello Eric and DrAmine.
In fact, it’s like the bottom plate has some holes where the fluid enters and leaves with a certain velocity defined by a boundary condition: (du/dy = alpha/ sqrt(k)) * (ui – um). That is, I need to set this condition exactly on the bottom wall.
Note that if this problem were to be solved analytically, I would have two boundary conditions.
(1) When y = 0 ==> du/dy = alpha/ sqrt(k)) * (ui – um)
(2) When y = h ==> u = 0
For the top plate the boundary condition it’s just a no-slip condition that can be set easily by fluent. But on the bottom plate I would need to put the equation: du/dy = alpha/ sqrt(k)) * (ui – um).
In short, what I really need to know how I can put an equation as a boundary condition on the bottom plate.
!Note that the plates are fixed.
September 20, 2022 at 6:52 amDrAmineAnsys Employee
Your BC looks after providing a shear stress to the Wall BC. You can explore that.
September 21, 2022 at 5:33 pmMr Eri MMSubscriber
Ok DrAmine, thank you.
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