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3d Laminar Flow

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Good Afternoon

I´m trying to run a very simple 3d simulation about an air flow that flows through a cylinder (radius=1,75mm) inscribed in a cube(side=4.3mm). Now, when I put between the inlet and outlet a fixed value of pressure (2000Pa) the simulation run without any problem; But if instead of the value of inlet pressure I put value of the mass flow 0.0007 [Kg/s] the solution does not converge. I tryed to change many settings (solver, tolerance and mesh) but it seems to work just for a very small amount of flowing air, like 13e-9[kg/s], that is a very small value.
I run out of ideas, can please someone help me to figure out on what I have to focus my attention.
Thank you in advance.

Renato Baldanzini

3 Replies Last Post 27.07.2016, 13:48 GMT-4
Jeff Hiller COMSOL Employee

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Posted: 8 years ago 27.07.2016, 11:20 GMT-4
Hi Renato,
Could it be that at the higher of the two mass flow rates the flow is turbulent?
Jeff
Hi Renato, Could it be that at the higher of the two mass flow rates the flow is turbulent? Jeff

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Posted: 8 years ago 27.07.2016, 13:09 GMT-4
Hi Jeff

I've thought the same thing and I tried to use the
the turbulent flow instead laminar flow.. the simulation run but the result
is too much different of what I expected.
I going to try with different setting another one time tomorrow.
Can maybe help me to choose a suitable solver for this case and in which
kind of setting of it I have to pay attention?
Thank you for the answer.
Regards
Renato
Hi Jeff I've thought the same thing and I tried to use the the turbulent flow instead laminar flow.. the simulation run but the result is too much different of what I expected. I going to try with different setting another one time tomorrow. Can maybe help me to choose a suitable solver for this case and in which kind of setting of it I have to pay attention? Thank you for the answer. Regards Renato

Jeff Hiller COMSOL Employee

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Posted: 8 years ago 27.07.2016, 13:48 GMT-4
Please contact COMSOL's technical support team through www.comsol.com/support/ if you need further assistance with your modeling.
Best regards,
Jeff
Please contact COMSOL's technical support team through www.comsol.com/support/ if you need further assistance with your modeling. Best regards, Jeff

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