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-   -   two fluid (http://www.cfd-online.com/Forums/flow-3d/72263-two-fluid.html)

great1427 January 31, 2010 02:00

two fluid
 
Hi, everyone!

I have a question about Flow 3D.

If i want to design a model for two fluids, A and B.

The initial condition is that A fluid is all in the tank.

The inflow is B, and how to do to set Q and H.

thanks your help.

MuxaB February 1, 2010 00:40

Is Q the flow rate? What is H?

great1427 February 1, 2010 05:27

Q is flow rate.

H is fluid height.

MuxaB February 1, 2010 10:19

fluid A is below H and fluid B above? Is Q the flow rate of fluid B? no fluid A is entering at the boundary, right?

great1427 February 1, 2010 11:15

the A fluid and B fluid are the same height.

the A fluid is like a reservoir.

the B fluid is like sediment flow. And the boundary is B's flow rate.

No A fluid enter at the boundery.

thanks a lot.

MuxaB February 1, 2010 23:46

Quote:

Originally Posted by great1427 (Post 244459)
the A fluid and B fluid are the same height.

the A fluid is like a reservoir.

the B fluid is like sediment flow. And the boundary is B's flow rate.

No A fluid enter at the boundery.

thanks a lot.

How can you have sediment fluid B flow without fluid A?

In any case, you can define both fluid height and flow rate at an x or y mesh boundary using the flow rate BC. If you are using the two-fluid model, then the fluid fraction at the boundary controls the A/B mixture: F=1 - fluid #1 (A), F=0 - fluid #2 (B). If you use the sediment scour mode instead, then you can define the sediment concentration at the boundary directly. In that case, sediment is not treated as fluid, but rather as a concentration of sediment in fluid #1.

great1427 February 3, 2010 22:46

And i have a question.

how about to set the mass source?

If i want the B fluid that is salt flow,then i have to set the model that is fluid 2,right?

however, i don't kown how to set the Mass-moment sources and Mass sources.

if you can, give an example.

thanks a lot.


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