Step-by-Step Tutorial: Homework of Session 4


#276

Hi @nvashi,

I mean in the CAD program itself. If you struggle merging the components, write me a private message. I will try to merge it with Creo 3.0.

Cheers,

Jousef


#277

Moved conversation with @nvashi to private.


#278

I got this error while running the simulation:

“The job execution was aborted, possibly due to a numerical instability. Review the log to identify reasons: unphysically large field values, extremely small time step size, etc. Modifying numerical settings and time step size could resolve the issue.”

Someone knows how to fix it?


#279

Hi @andresuriegas,

counter-check the parameters you typed in. If the error is still there, let me know.

Best,

Jousef


#280

I’m running the mesh again, I had one value slightly different, I’ll let you know if it worked. Thanks :slight_smile:


#281

@Milad_Mafi
Hi, in session 2 you said you would provide us with a tool to calculate k and omega in the final session, I have skipped through video 3 and 4 yet I have not seen anything regarding calculations or equations of k or omega. Please guide me to the location of the tool or a reference to calculate k and omega. Sorry if I missed it in the video, I am doing an assignment on design of a road going race car and I am using the videos as reference to perform CFD simulations using Simscale. All I could find on the web was this:https://www.cfd-online.com/Wiki/Turbulence_free-stream_boundary_conditions but the values I calculated do not match yours

Thanks so much


#282

Hello, I tried one wing setup with different resolutions of the stl files. There is a huge difference in lift/downforce (-131/110) and a rather small in drag (26,8/24,8).
Simulation 1_FW_V4 vs. Simulation 1_FW_V4_fine
https://www.simscale.com/workbench?publiclink=9b855853-d70e-43cc-8672-1e3ac80bc10e
Is such a high influence of the resolution realistic?
Thank you in advance.
Kind Regards
Andreas Fischer


#284

Hi Andreas (@andreas_fischer),

looking at the plots in the second run (the fine one) it seems that they are not really converged. Can you try running it for a bit longer?

Tell me if that had some influence on your results.

All the best!

Jousef


#285

Hello Jousefm,

I tried it with a longer run time and the impact on the result was pretty big:

Simulation 1_FW_V4_fine_Runtime: Drag 28,1 Lift -140,0
https://www.simscale.com/workbench?publiclink=9b855853-d70e-43cc-8672-1e3ac80bc10e
The task was to increase the downforce and the efficiency compared to the front wing in the second homework.

For the wing of the second homework I got 19,67/-112. Is that a realistic result for the comparison?

Thank you in advance.

Kind Regards
Andreas Fischer


#286

Hi @andreas_fischer!

Let me get back to you soon. Will have a look at the simulation and see if you can work with the results.

All the best!

Jousef