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My geometry is 3D I am designing a heat exchanger and similations are done in comsol 5.2a multiphysics. In my geometry one is heat domain and other one is fluid domain. The velocity profile in the fluid domain was not accurate, I want increase elements of fluid domain only can someone please help how to proceed it?

Now total elments in fluid domain are 280,000K

I need in that domain like 550,000K ]]>

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For questions specific to your modeling work, please contact our support team.

Online support center: https://www.comsol.com/support

Email: support@comsol.com

I’m doing simulations to find a contour or surface having 875 gauss field.I’ve two permanent ring magnets and i want to visualize the 2D field.while doing adaptive mesh confine following error coming during simulations……Pl can anyone tell me where is the error?..Thank you

“Failed to find a solution.

Attempt to evaluate negative power of zero.

Function: ^

Failed to evaluate temporary symbolic derivative variable.

Variable: comp1.mf.normBVDN${realdot7}, Defined as: (((realdot(comp1.mf.Br,comp1.mf.Br)+realdot(comp1.mf.Bz,comp1.mf.Bz))^(-0.5))*0.5)

Failed to evaluate expression.

Expression: d((comp1.mf.normB-0.087499999999999994),{realdot7})

Returned solution is not converged.

– Feature: Stationary Solver 1 (sol3/s1)”

The functional you choose does not need to converge to zero, no. In the case shown here, for example, it does not converge to zero. The algorithm is improving the accuracy of this functional by adjusting the mesh.

Regarding “Longest” vs. “Mesh Initialization”. The “longest” or “regular” methods will always work, but will only refine the mesh. The “mesh initialization” can both refine and coarsen the mesh but may, in rare circumstances, fail. There is no one method which will always be best for every case, you may want to try both. ]]>

A second question is about the use of “Longest” vs. “Mesh Initialization” as refinement method: I cannot find an explanation on what the difference is an I cannot chose the best for my model.

Thanks,

Roberto

]]>http://www.comsol.com/blogs/learning-solve-multiphysics-problems-effectively/

In particular, meshing considerations are a topic we’ve addressed before:

http://www.comsol.com/blogs/how-to-implement-mesh-refinement-study/

http://www.comsol.com/blogs/meshing-considerations-linear-static-problems/ ]]>