[fazaghifari]

Hello

So I have this unresolved problem since a few weeks ago. I want to trap a water inside a cylinder domain with density profile and buoyancy model. The BC at the bottom of the cylinder is free-slip wall since I don't want the water going down because of the gravity. The BC at the top is opening BC with opening pressure 0 Pa. And the BC at the side is opening BC with opening pressure 0 Pa since I want to allow the water coming in and out.

And here's the problem. When I look at the result, the water is coming out of the domain from the side because of gravity.

So, what should I do to make the water is trapped inside of the domain, but the boundary is allowing the flow to come in and out?

Well, actually I can impose an opening BC with velocity U, V, W with 0 m/s. But it doesn't allow the water to come in and out.

note: I use Ansys CFX on this model.

Thanks,
Best regards,

[BlnPhoenix]

Originally Posted by fazaghifari

So, what should I do to make the water is trapped inside of the domain, but the boundary is allowing the flow to come in and out?

This doesn't make much sense. You either want the water to be contained in your container, or you want it to leave.

Can you perhaps describe what you want to model, so one can try to help to get this straight.

[fazaghifari]

Originally Posted by BlnPhoenix

This doesn't make much sense. You either want the water to be contained in your container, or you want it to leave.

Can you perhaps describe what you want to model, so one can try to help to get this straight.

Actually, I just want to model a part of the bottom of a lake or sea.

[BlnPhoenix]

Hmm, interesting. I'm not sure how you can do this actually. Can you model the whole lake very coarse and refine it locally where you need it? Very interesting problem..

[fazaghifari]

So, I cannot only model the domain that I need? I mean although I have a very coarse mesh, it will be very big because the lake area is about 10 km^2 .

[BlnPhoenix]

Originally Posted by fazaghifari

So, I cannot only model the domain that I need? I mean although I have a very coarse mesh, it will be very big because the lake area is about 10 km^2 .

I don't see how at the moment. Has your lake special boundary conditions or is it just standing still all the time?

Maybe you can have inlet on one side and outlet on the other, that would mean that there is constant flow from one direction to the other though..

[FMDenaro]

Originally Posted by fazaghifari

Actually, I just want to model a part of the bottom of a lake or sea.

Maybe you can adopt periodic BC.s as we did here https://www.researchgate.net/publica...blicationTitle

[e_cfd]

Originally Posted by fazaghifari

Hello

So I have this unresolved problem since a few weeks ago. I want to trap a water inside a cylinder domain with density profile and buoyancy model. The BC at the bottom of the cylinder is free-slip wall since I don't want the water going down because of the gravity. The BC at the top is opening BC with opening pressure 0 Pa. And the BC at the side is opening BC with opening pressure 0 Pa since I want to allow the water coming in and out.

And here's the problem. When I look at the result, the water is coming out of the domain from the side because of gravity.

So, what should I do to make the water is trapped inside of the domain, but the boundary is allowing the flow to come in and out?

Well, actually I can impose an opening BC with velocity U, V, W with 0 m/s. But it doesn't allow the water to come in and out.

note: I use Ansys CFX on this model.

Thanks,
Best regards,

You might use pressure outlet BC (in fluent ) and write a udf for the static pressure for the side boundaries (changing with the depth).

[fazaghifari]

Thank You