Creeping flow, inflating device. Inlet works only for coarser meshes

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I'm pretty new to COMSOL Multiphysics, so there is probably some trivial issue I'm not getting.

I'm modelling a cross section of a polyethilene channel getting filled with water (I'm using an inlet at constant pressure and it inflates until the pressure drop gets to zero). Right now I can get it to inflate if I use the extremely coarse mesh option, but for finer meshes it does not work (I used a domain probe, for finer meshes it does not register anything). Any idea on what I'm not getting? I think it's either the meshes (I tried to play with the sequence, with no results) or some boundary condition maybe? Any advice is welcome.

Even when I inflate it, the simulation does not converge, but that does not really worry me for the moment. In case it may be useful, this is the error it gets when it stops: "Undefined value found in the equation residual vector. There are 3 degrees of freedom giving NaN/Inf in the vector for the variable comp1.spatial.u."

I can upload the model if needed

0 Replies Last Post Aug 8, 2022, 9:51 a.m. EDT
COMSOL Moderator

Hello Beniamino Rocchi

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