[esgee]

Hi,

I'm new to CFD and I couldn't find any solution with the Gambit tutorials I looked. My problem is that I have an open channel where water is flowing to a container. Here is very simple picture about it

http://img14.imageshack.us/img14/2968/channelt.png

The flow is surrounded by three walls and air where atmospheric pressure is acting. I'm having problems how to mesh the system (channel + container) 3D grid. I would appreciate any comments, thanks in advance.

[-mAx-]

what kind of problems?

[esgee]

I am living in thought that only closed volumes can be meshed. My channel is open to air on its one face so how can I mesh its interior? Is multiphase flow (water and air) the only solution?

[-mAx-]

you need definitively a closed volume.
Yes Multphase flow

[esgee]

Would this solution work:
I'll set to the boundary conditions that the three walls are stationary and on the fourth wall, there is no shear stress

[-mAx-]

you are talking about the fluent side (BC etc...) and you can open a new thread in the right subcategory (I don't have any experience with open channel) , but you need first a 3d mesh

[subha_meter]

You need a "volume : brick" to assign the computational domain. You can try applying "wall" BC at 3 sides and "Pressure outlet" on the top surface and provide atmospheric pressure condition over there.

For IN, you can use "mass flow inlet/velocity inlet" & for OUT...."outflow" BC.

For open channel flow, you need to use VOF multiphase model to track air/water interface.

[hossein65]

Hi;
The best B.C for upper side of an open channel is "symmetry".
that also helps the free surface level change automatically.