# pressure boundary

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 May 28, 2009, 00:46 pressure boundary #1 New Member   linfangcai Join Date: May 2009 Posts: 9 Rep Power: 11 Does pessure boundary mean new fluid flows into the computional domain under the influence of pressure?

 June 1, 2009, 12:01 #2 Member   MC Join Date: Mar 2009 Posts: 56 Rep Power: 11 Hi~ 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. MC

 June 3, 2009, 22:03 #3 New Member   linfangcai Join Date: May 2009 Posts: 9 Rep Power: 11 Thank you,melissa! I understand.

 October 20, 2009, 02:38 #4 New Member   Sean Join Date: Oct 2009 Posts: 3 Rep Power: 11 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)?

 October 21, 2009, 01:15 #5 Senior Member   michael barkhudarov Join Date: Mar 2009 Posts: 335 Rep Power: 12 Nikesandman, 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.