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Laminar flow through a cube with a hole at bottom
Posted Nov 26, 2015, 12:00 p.m. EST Fluid & Heat Version 5.2 3 Replies
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Dear Comsol users,
I am relatively new to comsol, but have been working for quite sometime.
I was just wondering why is it so difficult (not converging even after 100 iterations) to solve a laminar fluid flow in box having a hole (outlet) at the bottom.
Problem description: The 3D box having no slip at all the walls except the inlet wall (face). The exit boundary is "no viscous stress" where the aperture diameter is 60% of the box edge, opposite to the inlet face. The inlet velocity is given at 0.1 m/s. The mesh is physics controlled "normal".
I have attached the comsol for details, if anyone is interested.
Is is something very simple that I am missing.
My final goal is to apply the periodic boundary conditions to the opposite faces in the direction transverse to the primary flow.
Regards,
Sourav
I am relatively new to comsol, but have been working for quite sometime.
I was just wondering why is it so difficult (not converging even after 100 iterations) to solve a laminar fluid flow in box having a hole (outlet) at the bottom.
Problem description: The 3D box having no slip at all the walls except the inlet wall (face). The exit boundary is "no viscous stress" where the aperture diameter is 60% of the box edge, opposite to the inlet face. The inlet velocity is given at 0.1 m/s. The mesh is physics controlled "normal".
I have attached the comsol for details, if anyone is interested.
Is is something very simple that I am missing.
My final goal is to apply the periodic boundary conditions to the opposite faces in the direction transverse to the primary flow.
Regards,
Sourav
Attachments:
3 Replies Last Post Nov 27, 2015, 9:43 a.m. EST
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Posted:
9 years ago
Can't open your file as I have not installed 5.2 but your mesh may be insufficient, depending on the size of the box.
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Posted:
9 years ago
Dear Dr. Ooi,
Unfortunately there is no option to save the model file in lower compatible version. Just a bit of information about the mesh, if it helps:
============================================================
Number of vertex elements: 13
Number of edge elements: 736
Number of boundary elements: 30076
Number of elements: 486882
Free meshing time: 10.49s
Minimum element quality: 0.154
============================================================
The box size is 1mx1mx0.5m
Regards,
Sourav
Unfortunately there is no option to save the model file in lower compatible version. Just a bit of information about the mesh, if it helps:
============================================================
Number of vertex elements: 13
Number of edge elements: 736
Number of boundary elements: 30076
Number of elements: 486882
Free meshing time: 10.49s
Minimum element quality: 0.154
============================================================
The box size is 1mx1mx0.5m
Regards,
Sourav
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Posted:
9 years ago
Hi Sourav
What value for viscosity are you using in your system, is it quite small? If so you might have a rather high Reynolds number judging from the dimensions of your box. As a simple check you could tick the stokes flow check box under Laminar flow Physical model which throws away the inertial terms and see if your model now converges.
Stevie
What value for viscosity are you using in your system, is it quite small? If so you might have a rather high Reynolds number judging from the dimensions of your box. As a simple check you could tick the stokes flow check box under Laminar flow Physical model which throws away the inertial terms and see if your model now converges.
Stevie