CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLOW-3D (
-   -   pressure boundary (

fang May 27, 2009 23:46

pressure boundary
Does pessure boundary mean new fluid flows into the computional domain under the influence of pressure?

melissa June 1, 2009 11:01

The fluid fraction determines what fluid is entering. If you have a tank with fluid and void and you set the top boundary to pressure and leave the fluid fraction to 1 then fluid 1 will enter the tank. If you set the fluid fraction to zero and a pressure boundary then the void will use that pressure and no fluid will enter the domain. However if you are using two-fluid then then having fluid fraction as 0 will allow fluid 2 to enter the domain. So fluid fraction of 1 for fluid 1 and fluid fraction 0 for void/fluid2.:)

fang June 3, 2009 21:03

Thank you,melissa!
I understand.

nikesandman October 20, 2009 01:38

Hi Melissa,

Would this mean that for a casting simulation you would want to include some void region (considering that the shot sleeve is not completely full of material)?

MuxaB October 21, 2009 00:15


referring to your original post, you can include the shot sleeve in your simulation to replace the inlet boundary. The plunger can have a time-dependent velocity just like in the real machine.

All times are GMT -4. The time now is 16:33.