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Old   August 27, 2012, 05:34
Default outlet conditions
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henry
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hey im new to CFX and am just starting a project at a new company where i am looking at two phase flow, water particles in air through a vane/vent type enclosure.
i am having problems with my outlet conditions, is it possible to not have to input and conditions here, I have tried just setting the static pressure but this puts up a wall which restricts flow, setting a velocity changes the flow through the vent.. I also tried using an opening as opposed to an outlet but it crashed every time. Not sure If theres probably a very simple solution to this problem.??
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Old   August 27, 2012, 07:39
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Hi

i would enlarge the outflow region and evaluate the plane where your former outlet region was or evaluate a bit downstream

otherwise the results could be compromised because the outlet condition forces the eddy to end upstream(noticed that in an OpenFOAM-case with outlet-condition) or you could have problems with convergence(my experience with a heatflow analysis in an Ansys-case where i tried to set the inflow-temperature of the opening-condition with an massFlowAve(T)@outlet-expression) and maybe the missing convergence causes the solver to crash in your case
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Old   August 27, 2012, 07:55
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Glenn Horrocks
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Can you post an image of what you are modelling and the flow applied to it?
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Old   August 27, 2012, 21:03
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henry
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this is the mesh, I need to model the water particles track where they become trapped in the grooves of the vent.
Attached Images
File Type: jpg sim_10.jpg (94.3 KB, 13 views)
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Old   August 28, 2012, 07:23
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If the flow is high Re then your exit boundary is too close. You need to move it downstream - bratzinger's comment is correct.
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