Menu

Discussion Forum

New Discussion
Filtra

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Mass Balance Tracking

Posted 25 feb 2011, 00:37 GMT-5 Fluid & Heat, Computational Fluid Dynamics (CFD), Modeling Tools & Definitions, Parameters, Variables, & Functions, Studies & Solvers Version 4.0a 2 Replies

Ranjeeth Naik
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Hello,

I am trying to solve a rectangular domain fluid flow and heat transfer problem (please look at the attached figure).
I had following questions:

1. The problem was solved using Comsol 4.0a with “pressure-point constraint” of 0 Pa at point “c”. The “Laminar Flow” and “Heat Transfer” models were used. The stationary solver gave a converged solution. However on checking the mass balance for the boundaries a mass deficit was observed.

Is there a method to ensure that the mass, momentum and energy balances are satisfied accurately during the process of solving? And also can this be tracked/ monitored during the process of solving? How can the accuracy be improved?

2. Now if the same problem is solved using Comsol 4.0a with “pressure-point constraint” of 0 Pa at point “a”, the stationary solver does not solve. How can this problem be resolved?

Also I am using a free triangular mesh with "extremely fine" size.

Thank You,
Ranjeeth
2 Replies Last Post 4 mar 2011, 16:16 GMT-5
Ranjeeth Naik
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 4 mar 2011, 11:30 GMT-5
does anyone know how to do it?

Thanks,
Ranjeeth
does anyone know how to do it? Thanks, Ranjeeth
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 4 mar 2011, 16:16 GMT-5
Hi

I'm not sure its the pressue point, have you noticced that you have NOT coupled the velocity field from the fluid flow to the HT (change in the Model Input tab). And if you have a fluid, then you should use HT in fluid thermal physics and NOT SOLID

currently you have only conduction in your results, no fluid flow /(I'm running v4.1 so there might be differences as v4.0 was not really ironed out, particularly not for CFD

--
Good luck
Ivar
Hi I'm not sure its the pressue point, have you noticced that you have NOT coupled the velocity field from the fluid flow to the HT (change in the Model Input tab). And if you have a fluid, then you should use HT in fluid thermal physics and NOT SOLID currently you have only conduction in your results, no fluid flow /(I'm running v4.1 so there might be differences as v4.0 was not really ironed out, particularly not for CFD -- Good luck Ivar

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.

Suggested Content