Hello everybody! I've been trying to design this nosecone using multisection surfaces. The thing is, whenever i add this lateral spline, i get an error which i dont know how to solve. Is there any way to solve this? Please let me know if there's anything other info i can provide to help
Hello everybody! You might remember me from my post from earlier this week in which i asked a similar question to the one posed in the title. Since then, thanks to your guys' help, my results have converged nicely and my residuals have dropped and stabilized significantly. However, i'm still striving for better residuals to try and earn some extra points with the judges during the FSAEBR competition.
Here's a list of all the things i've changed since that last post. At the time i was using a polyhedral mesh with 9 million cells and the segregated solver:
- changed a1 and realizability coefficients to 1 and 1.2, respectively (as per the best practices for fsae and external aero guides posted on siemens support center) and increased the size of the domain
this lowered my residuals significantly and helped my reports stabilize. (images 1 and 2).
However, when
- i increased the refinement near the ground
(to try and improve undertray convergence), the reports actually oscillated more (image 3 and 4) so i stopped the simulation midway since i didnt i simply dont have the time to let it run for more iterations.
After this i decided to try the
-trimmed mesher,
and followed the same tutorial on siemens support center. This is the mesh i'm using right now, to which i'll provide the details later, (11,5 million cells). My residuals were similar, but the undertray still didnt converge. (images 5 and 6)
At last, this is my current iteration, in which i started using the
-coupled solver, with cfl 100
it takes ages to complete 1000 iterations (>12 hours), but it finally converged. (images 7 and 8)
Now, for things i know i still have to do:
-improve the refinement at the leading edge of airfoils (image 9)
-improve the refinement of the tubes, which are really jagged (image 10)
My questions are: how can i lower my residuals even further within my 16 gigs of ram (or is it impossible and i should outsource it to a teammate with a beefier pc (my unis pcs suck))? More importantly, which tools should i use to identify problems with the mesh and how do i interpret them? Also regarding the tubes: how should i set the prism layers so that i can have a high y+ approach towards them? Should i go back to the polyhedral mesh?
I will still be applying some things a fellow redditor suggested, but in the meanwhile, any input will be extremely appreciated
Once again, thank you guys for your patience and help. I've learned a lot from these comments and hope to one day be able to help other people with similar questions🙏
Hey all! I'm part of my unis FSAE aero team and I'm having trouble with convergence in full car simulations, especially with the undertray and rear wing. I'd like to know whether there are things that could be improved with the meshing.
I will attach pictures of what i think is the best iteration so far, which has 9.5 million cells. I have tried using i trimmed mesher and my pc would just give up with the amount of cells i was trying to push, all while the results weren't really any better than using a poly mesher.
Additionally, it be nice if the new simulations could be run in less than 24 hours on a notebook with 16gb RAM and a core i7 10750H.
I'll be glad to provide any additional information that may be found useful.