mesh adaptation failure

[khanal.simant]

Hello,

I am trying to carry out mesh adaptation but unfortunately the analysis stops immediately after I click the solve button. I tried with a dummy model with few elements just to see if there was an issue of mesh but nothing works. What could be the issue and how to solve it?

Thanks,

Simant

[karol.suchon]

Probably that is an overall issue with the software version. In CFD 2023 I was not able to force the software to run mesh adaptation in most of the models.
You could send me the current one and I will try to do it on my side.
BR
Karol

[khanal.simant]

Hi,

Please find attached the support file. This is kind of urgent so kindly look into it at the earliest.

Thanks,

Simant

[karol.suchon · Accepted solution]

I tried a few things to force the software to run mesh adaptation but it failed every time.

In that situation, I could only suggest you refine the mesh manually.

BR
Karol

[khanal.simant]

Thanks Karol, I would do it manually,

Could you help me out on how to perform simulation by enabling radiation. I tried several times but somehow temp/pressure fails to converge and the simulation crashes. 

I have tried with the last model which I sent you.

Thanks,

[khanal.simant]

Hi Karol,

Could you please check on radiation for the attached model. I am unable to get the results for the simulation once I enable radiation as the temp./pressure crashes and does not converge.

Thanks,

[karol.suchon · Accepted solution]

With radiation there are two issues which you need to solve:

• Air emissivity cannot be equal to 1. Edit the material and set emissivity to 0.01
• The radiation is a heat exchange between the solid parts,  so the only fluid volume which does not have contact should be the outside volume, so in radiation, you need to resume all solid suppressed parts.

That's why you get the divergence, radiation rays hit on the fluid surface and are absorbed, the air has very low conductivity so which generated a huge temperature pick, and the solver is not able to handle it.

Check if that helps you to solve the issue.
BR
Karol

[khanal.simant]

Hi Karol,

I am still facing issues with convergence. Could you please check if I have missed something. I have attached the support file and the image of the result graph.

Thanks,

Simant

[khanal.simant]

Hi Karol,

By suppressing all the solid parts the solution does not crash which is good, but for my simulation I need to include the B.C for the internal fluid flow and for which I have to suppress the solid bodies.

What should be the strategy in that case?

Thanks,

Simant

[karol.suchon]

Hello Khanal, at this moment I am not able to run your simulation, too many of them are qued so I could only give you some advice:(
But that's great that you solve the biggest issue. Probably you have now a problem with the internal flow condition which could work only if they are applied to the surface which belongs only to the fluid body. In that situation create small bodies on the inlet and suppress them, the body should only contact the fluid with the face where you applied the BC and should be surrounded by other solid bodies. 
BR
Karol

[khanal.simant]

Thanks for your quick reply.

I have done the exact same thing which you can also see in my model. Please check that when you have time.

[karol.suchon]

Khanal, send me the PM 🙂

[khanal.simant]

Hi Karol,

Can you please check pm.