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Boundary conditions don't seem to hold throughout simulation
Posted Nov 13, 2019, 9:59 a.m. EST General, Parameters, Variables, & Functions, Results & Visualization Version 5.4 0 Replies
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Hello!
I am currently working with the microfluidics module and using the laminar two phase flow, phase-field work. For my particular case, I want to use an outlet flow (e.g. 5 μL/min) while leaving the two inlets I have in the module at a certain pressure.
My issue lies on the boundary condition. I computed the surface integral of the velocity at the outlet boundary and, whereas in the beginning there is not a significant difference in the theoretical value (the one I used as input) and the calculated one (i.e. the integral on COMSOL), but after some time, the calculation becomes around 4 times bigger than want I have inputed (refer to annex figure, it represents the relative difference between the two values).
Does anyone have any suggestion to why this happens and how to make this right?
Thanks in advance!!
EDIT I went through the problem and I figured that my flux was not corretcly calculated. I used intop2(spf.U) instead of intop2(nxpf.ux+nypf.uy+nz*pf.uz)
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Hello André Moura
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