Surface roughness fluid flow

Please login with a confirmed email address before reporting spam

Hi, I would like to add different surface roughness for a simple channel flow case. I see the option to do that for any of the turbulence models under the Turbulent Flow interface. But, is there a way we can add it for laminar flow? Is it the practical limitation that surface roughness can induce turbulence, that we don't have this option in COMSOL?


2 Replies Last Post Jul 5, 2022, 10:44 a.m. EDT
Jim Freels mechanical side of nuclear engineering, multiphysics analysis, COMSOL specialist

Please login with a confirmed email address before reporting spam

Posted: 2 months ago Jun 9, 2022, 9:48 a.m. EDT

One way would be to examine the surface roughness terms added into the turbulence model equations (view equations). Then retrieve those terms and save them to a temporary file. Next add those same terms into your laminar-only equation system in a similar manner as the turbulence equations. Take care to make sure all the variables/parameters used in these terms are correctly coupled and implemented. This will require you to understand the physics required for this term. Then test it out.

Alternatively, you could add the effect of the surface roughness through a body-force term which would be more of a global effect and cause an overall pressure change due to the surface roughness (see the implementation equivalent in 1D to understand).

-------------------
James D. Freels, Ph.D., P.E.
One way would be to examine the surface roughness terms added into the turbulence model equations (view equations). Then retrieve those terms and save them to a temporary file. Next add those same terms into your laminar-only equation system in a similar manner as the turbulence equations. Take care to make sure all the variables/parameters used in these terms are correctly coupled and implemented. This will require you to understand the physics required for this term. Then test it out. Alternatively, you could add the effect of the surface roughness through a body-force term which would be more of a global effect and cause an overall pressure change due to the surface roughness (see the implementation equivalent in 1D to understand).

Please login with a confirmed email address before reporting spam

Posted: 1 month ago Jul 5, 2022, 10:44 a.m. EDT

Hi James Thank you, this is very helpful. It definitely would be useful if this was a term directly available under laminar flow since the links already exist for turbulence.

I'll give this a shot. Thanks !

Advitya

Hi James Thank you, this is very helpful. It definitely would be useful if this was a term directly available under laminar flow since the links already exist for turbulence. I'll give this a shot. Thanks ! Advitya

Reply

Please read the discussion forum rules before posting.

Please log in to post a reply.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.