Outlet conditions in BuoyantFoam

jont · October 13, 2007, 14:58

Hi,

having some problems with outlet-conditions in a BuoyantFoam simulation. Case is basically the same as the hotRoom tutorial case, BUT with an inlet and an outlet with given pressure both at inlet and outlet (and hence producing a "chimney" effect). On the inlet pressureInlet is used, and on the outlet pressureOutlet. The last means that a fixed value is used for the pressure at the outlet, but for all other variables zeroGradient is used. This seems to work fine in most cases, but in some situations a very small "backflow" develops at the outlet, and as soon as this happens the solution becomes unstable (starting with the temperature). Are there other, "better suited", boundary conditions I can use in this situation?

gschaider · October 15, 2007, 05:27

Check out the inletOutlet-class of boundary conditions (fixedValue for inflow, zeroGradient for outflow) in the table 6.4 of the UserGuide. Use that for the temperature.

jont · October 15, 2007, 08:55

Thanks!

Thought they were only applicable to pressure, but seems to be running...

/jon

October 13, 2007, 14:58	Hi, having some problems w	#1
jont New Member Jon Tegner Join Date: Mar 2009 Posts: 7 Rep Power: 17	Hi, having some problems with outlet-conditions in a BuoyantFoam simulation. Case is basically the same as the hotRoom tutorial case, BUT with an inlet and an outlet with given pressure both at inlet and outlet (and hence producing a "chimney" effect). On the inlet pressureInlet is used, and on the outlet pressureOutlet. The last means that a fixed value is used for the pressure at the outlet, but for all other variables zeroGradient is used. This seems to work fine in most cases, but in some situations a very small "backflow" develops at the outlet, and as soon as this happens the solution becomes unstable (starting with the temperature). Are there other, "better suited", boundary conditions I can use in this situation?

October 15, 2007, 05:27	Check out the inletOutlet-clas	#2
gschaider Assistant Moderator Bernhard Gschaider Join Date: Mar 2009 Posts: 4,225 Rep Power: 51	Check out the inletOutlet-class of boundary conditions (fixedValue for inflow, zeroGradient for outflow) in the table 6.4 of the UserGuide. Use that for the temperature. __________________ Note: I don't use "Friend"-feature on this forum out of principle. Ah. And by the way: I'm not on Facebook either. So don't be offended if I don't accept your invitation/friend request

October 15, 2007, 08:55	Thanks! Thought they were o	#3
jont New Member Jon Tegner Join Date: Mar 2009 Posts: 7 Rep Power: 17	Thanks! Thought they were only applicable to pressure, but seems to be running... /jon

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