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How to improve the velocity profile to be close to the theoretical values.

Posted Mar 11, 2013, 1:06 a.m. EDT Computational Fluid Dynamics (CFD) 1 Reply

Jihye Kim
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I'm trying to generate velocity profile in cylindrical tube (3D, laminar flow module) containing water. I expected it to be parabola shape of velocity profile along the axial direction with zero velocity on the wall (I set the wall as no slip). However, I see the right side of the tubing wall does not reach to zero velocity. Also, the velocity values that I get from comsol is not matching well with the theoretical value as shown in the attached plot. Could you tell me how to improve the velocity profile value from comsol? I already tried finer mesh, but it didn't really help.

P.S. Overall I connect this laminar flow module with heat transfer module. I use the velocity values from the laminar flow module in the heat transfer module to see the temperature gradient along the z-direction by varying the flow rates.
1 Reply Last Post Mar 20, 2013, 5:08 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Mar 20, 2013, 5:08 p.m. EDT
Hi


the velocity profile depends also on fluid properties, and COMSOLs fluid properties are often Temp and pressure dependent, are you sure you have the same conditions as your model ?
For the no-slip conditon to work well in FEM you need a fine mesh along the boundary, do you use fine "boundary mesh" as prescribed for CD ?

--
Good luck
Ivar
Hi the velocity profile depends also on fluid properties, and COMSOLs fluid properties are often Temp and pressure dependent, are you sure you have the same conditions as your model ? For the no-slip conditon to work well in FEM you need a fine mesh along the boundary, do you use fine "boundary mesh" as prescribed for CD ? -- Good luck Ivar

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