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boundary condition for straight 3D open chnannel

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Old   March 15, 2010, 03:47
Default boundary condition for straight 3D open chnannel
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Mrityunjay sahu
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I am setting up a problem on 3D straight open channel flows........can any one suggest me the boundary conditions to be imposed during meshing in Gambit?
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Old   March 15, 2010, 06:25
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Vincent Meertens
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Hi,

I'm also doing a case with 3D open channel.

For inlet and outlet i use: Pressure Inlet and Pressure Outlet.
For your plate you should use wall. (in fluent this will be a stationary wall)
If you have a brick (flow volume) then your BC for the rest of the sides should be wall (in fluent i define them as moving walls with the same speed as the fluid)

Hope this helps.
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Old   March 15, 2010, 06:39
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Svetlin Philipov
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BC depends on what you know... inlet velocity, Pressure inlet, mass flowrate and so on.... we do not know that information....
Using Pressure inlet and Pressure outlet assume compressibility of the fluid that is not known also... BC must be set to property that you can compare to any reference value...... rearrange the question and ask again when you can give more details and have more information about the task....
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Old   March 15, 2010, 07:41
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wat about freesurface...........wat would be the BC for top surface
i have two option in it............
1. To apply pressure inlet
2. moving wall
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Old   March 15, 2010, 07:46
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Hey,

Philipov is right, i replied to soon...
I assumed it was just water and air with a constant inlet speed.

The free surface doesn't need a BC (if i'm correct ) This is done in Fluent and not in Gambit.
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Old   March 15, 2010, 07:57
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yeah buddy this is done in fluent after completion of meshing
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Old   March 15, 2010, 07:59
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but about boundary condition to free surface
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