Can you share your project as well as a picture of your pressure distribution @plakiasge?

Thanks!

Jousef

Can you share your project as well as a picture of your pressure distribution @plakiasge?

Thanks!

Jousef

Thank you very much @jousefm !

I couldnt see the solid_0_Barre in the list, that is why I could not find it before. I re-started the simulation and hope it finishes as soon as possible. Thank you again!

Best,

Vanessa

Absolutely no problem Vanessa (@vbarreda)!

Hope you enjoy the sessions so far! Let me know if you need help with anything.

Happy SimScaling!

Jousef

It seems to be fine. It was probably like the problem from @rishav997. Thank you for your respond @jousefm

can i get some more time to submit my homework for this session?, actually i confronted some issues in meshing, and now i am late in submitting my homework

@jousefm could you take a look at my convergence plot and let me know if there seems to be a mistake. We have not discussed the convergence plots specifically in this tutorial 3 but as I remember they are supposed to flat line towards the end which doesnāt seem to be the case in my project, although the individual forces have flat lined.

https://www.simscale.com/workbench/?pid=4962895595087045938#tab_0-0

Hi @nishank_a !

Question for you to make this more interesting and not just a question-answer-game. Would you say that the convergence is good enough with 10^{-4} or 10^{-5} ? Let me know what you think and discuss a bit

All the best!

Jousef

@jousefm

10^-5 is considered to be a well converged result though in complicated problems 10^-5 is a pretty hard value to get.

Hi @nishank_a!

I have found a very nice answer from @gholami on convergence in general:

The role of residuals in determining if simulation results are to be trusted should not be misunderstood. Reaching steady residuals means that the solution has converged to a value. Whether this value is correct or not can ultimately be concluded by monitoring the solution field.

There are a number of factors that could cause large pressure residuals. You could perform a convergence study to determine if results are reliable. In case of this simulation, consider the following:

Mesh quality could impose a lower limit on residual values. Even though your mesh looks good, convergence of the solution by refining the mesh should be studied. Specifically consider boundary vicinity and regions of high gradient.

Linear solvers have an impact on convergence behavior. You could try a different solver for pressure to see if residuals change.

Absolute and relative residuals must be considered carefully. We have had a discussion on thishere. As demonstrated, residuals must be chosen in accordance with all variables. In your case, relative pressure residual could be reconsidered.

This list is in fact longer. You could reconsider the choice of the turbulence model, turbulence wall treatment, numerical schemes, etc. However, be aware that the residual value in itself is not the issue, e.g. one could under-relax to get smaller residuals, but this does not improve the solution. Whatever you do, convergence of the solution field is the deciding factor.

For more information see this thread: **Residuals**

P.S.: Do you wish to get a SimWiki article for this subject to get a deeper understanding of the theory?

All the best!

Jousef

@jousefm

Thanks for the detailed reply. Iāll take a look at the points mentioned and move forward from there.

The wiki would really be helpful.

yes please review this issue, i am also getting this similar problem as multiple other usersā¦, could not figure out a fix though.

Hi @hur_rehman!

Are you talking about the oscillations in the convergence plots? If so please share your project. Trying to find the culprit

All the best!

Jousef

Hi @hur_rehman!

As mentioned in previous posts you might first counter-check everything you have done with the tutorial. If that does not help sometimes the log file says something about the problem. Feel free to share the project with me.

Best,

Jousef

Hi,

Iām having a problem with the simulation. After 20 to 30 minutes running it, shows a message saying āErrorā and nothing else. Iāve checked with the step by step tutorial and everything seems to be fine. Can anyone help me please?

Thanks in advance.

Hi @ricardo_3282, sorry for the small delay in my response.

Could you share the project you are referring to? Either @Get_Barried, @vgon_alves or me will check that out

Best,

Jousef

Hi @jousefm,

here 's the link to my project:

https://www.simscale.com/projects/ricardo_3282/fsae_2017-workshop-s3-_yaw_angle-analysis-simulation_1/

Thank you so much.

that seems to be the same issue like in this thread: **FSAE CFD meshing and simulation convergence issue**

Have to figure out whatās going on here.

Best,

Jousef

Hi @ricardo_3282,

Iām jumping in your project just now, but having a 1st look at your project, you need to put the same value to *fwheel* and *MRF Front* as you did for *rwheel* and *MRF Rear*:

Please, give me some feedback about your run after you fix it.

Cheers,

VinĆcius