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Error message after compute, modeling CFD of equipment in tunnel, advice? [CM 4.4]

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Hi, I'm a very very beginner in using COMSOL Multiphysics 4.4, I've never used it before, but I've done some tutorials from the installer.

Now I'm trying to compute this model (can be seen attached, "model.jpg"), studying about air flow flowing through this equipment in a tunnel.

But, I don't know why, I got this message error after choosing the "compute" command (the error message is also attached, "comsol_error.jpg"):

Failed to evaluate operator.
- Operator: mean
- Geometry: 1
- Boundary: 2 3 4 5 142
Mean operator requires an adjacent entity of higher dimension.
Failed to evaluate expression.
- Expression: mean(comp1.spf.C_mu)
Failed to evaluate variable.
- Variable: comp1.spf.C_mu
- Geometry: 1
- Boundary: 2 3 4 5 142
Failed to evaluate expression.
- Expression: nojac(max(11.06,((((0.5*(comp1.spf.C_mu^0.25))*sqrt(max(comp1.k,0)))*down(comp1.spf.rho))/(down(comp1.spf.mu)*(down(tremetric)^0.5)))))
Failed to evaluate variable.
- Variable: comp1.spf.d_w_plus
- Defined as: nojac(max(11.06,((((0.5*(comp1.spf.C_mu^0.25))*sqrt(max(comp1.k,0)))*down(comp1.spf.rho))/(down(comp1.spf.mu)*(down(tremetric)^0.5)))))
Failed to evaluate temporary symbolic derivative variable.
- Variable: comp1.spf.ep_w@VDN$comp1.k
- Defined as: ((1/((comp1.spf.d_w_plus*comp1.spf.kappav)*nojac(down(comp1.spf.mu))))*(nojac(down(comp1.spf.rho))*(comp1.spf.C_mu*((2*max(comp1.k,0))*(comp1.k>0)))))
Failed to evaluate expression.
- Expression: d(-comp1.ep+comp1.spf.ep_w,comp1.k)

Do you have any idea on why did this happen? How to solve this problem?
I will be grateful for any help/opinion you can provide.
Cheers.


2 Replies Last Post 14 mar 2014, 04:21 GMT-4
Mikael Noerregaard Nielsen

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Posted: 1 decade ago 13 mar 2014, 12:18 GMT-4
Hey John

I've never seen that particular error before but it could be related to your geometry or to your mesh. Have you drawn the geometry yourself or is it imported?

Is it possible for you to send the model itself?

Regards
Hey John I've never seen that particular error before but it could be related to your geometry or to your mesh. Have you drawn the geometry yourself or is it imported? Is it possible for you to send the model itself? Regards

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Posted: 1 decade ago 14 mar 2014, 04:21 GMT-4

Hey John

I've never seen that particular error before but it could be related to your geometry or to your mesh. Have you drawn the geometry yourself or is it imported?

Is it possible for you to send the model itself?

Regards


I drew the geometry by myself in AutoCAD 2010, and exported it as an *.stl file format, and them used COMSOL to import that file. Is this the proper way to import files from AutoCAD?

Sure it is possible, here's the model attached.

So, maybe I have to redesign the model again? Is it that COMSOL cannot create mesh for complicated models? (Or it could create mesh but with high possibility of having errors, warnings, etc.?) Thanks for replying my post Mikael.
[QUOTE] Hey John I've never seen that particular error before but it could be related to your geometry or to your mesh. Have you drawn the geometry yourself or is it imported? Is it possible for you to send the model itself? Regards [/QUOTE] I drew the geometry by myself in AutoCAD 2010, and exported it as an *.stl file format, and them used COMSOL to import that file. Is this the proper way to import files from AutoCAD? Sure it is possible, here's the model attached. So, maybe I have to redesign the model again? Is it that COMSOL cannot create mesh for complicated models? (Or it could create mesh but with high possibility of having errors, warnings, etc.?) Thanks for replying my post Mikael.

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