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az_f May 3, 2010 22:16

Boundary condition
I have a laminar blood flow that passes through a bifurcation I used high residual scheme with 10-5 residual. My problem is if I set up 3 mass flow rates(1 inlet and 2 outlets) I 've got a strange result with negative energy loss in whole system and very small pressure at inlet compared to two outlets. but the flow direction is still from inlet to outlets. Which I don't understand why?
but if I setup massflow at inlet and one outlet and use pressure zero at the other outlet the energy loss is positive and pressure at inlet is higher than outles.

I don't where the problem is? Is that mean a system with 3 mass flow is not stable??? ( I should mention that the flow distirbution is not symmetric)

Any Idea??


ghorrocks May 4, 2010 09:26

You cannot physically do 3 mass flow boundaries. The pressure is undefined and any imbalance in the flow rate cannot be corrected.

Read the documentation about implementing boundary conditions. It explains the recommended combinations of boundary conditions.

az_f May 4, 2010 20:16

Thanks Glen

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