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Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 11:23
by LVDH
Ok,
so I sent out the email with the submission links. If you do not receive it, you are not on the list. If you think you should be, please complain.

Also regarding the cooling issues, once more I would like to point to this here:
Image
https://mantiumchallenge.com/porous-media-openfoam/

And if you are not able to create evenly tesselated measurement surfaces, do not worry. I remesh all the measurement surfaces you send me, so they are the same for everyone. But if you are running with poorly tesselated surfaces for your own simulations, you are simply receiving incorrect results.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 11:24
by variante
All the cars that have been shown so far seem pretty solid! Till now we have images from wb92, Talno, jjn9128, CAEdevice (am i missing someone?). Aside from being all more beautiful and refined than mine, i'm noticing that they all have a conventional layout, very close to F1 (even though the rules give a lot of freedom in certain areas)...interesting.

CAEdevice's car is particularly detail rich. Like in 2019 F1, he seems to have gone for low AoA front wing, on the outer sections. That's particularly interesting to me.
Original nosecone too.

I guess it won't be long until i show mine, which will be quite different here and there...

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 11:54
by jjn9128
I wouldn't be too worried about me. I'm running a fast case (without suspension - where does suspension go? Can't go with bodywork because presumably that rotates with pitch, can't go with wheels because surely they're a rotating surface) and downforce is disturbingly low and drag is a high for where I was aiming. Only 600 iterations in but things have plateaued a bit.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 12:16
by CAEdevice
jjn9128 wrote:
17 Aug 2019, 11:04
Sorry I use abbreviations a lot. RWEP = Rear wing end plate.
No, they are not connected to the diffuser. I cutted all the geoemtry that has negative effects, the part of the endplate that remains was useful for the cooling (at first the sidepods where longer). I am not sure I will inlcude all the endplates in final release.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 12:19
by CAEdevice
variante wrote:
17 Aug 2019, 11:24
CAEdevice's car is particularly detail rich. Like in 2019 F1, he seems to have gone for low AoA front wing, on the outer sections.
Maybe it depends on the raw mesh of the FAST setup (the only I used, at the end), but the front wing 2019 layout (further simplified in my car, with only three sections) was easier to optimize than more complex solutions with vortex generators (2018) and more sections.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 13:59
by rjsa
I’m not submitting. Still get lift on the rear, still some parts missing.

I spent time I didn’t have on this and didn’t quite get there. Now 3 weeks out of town.

Let’s see if I can get something reasonable for race 3.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 15:02
by jjn9128
rjsa wrote:
17 Aug 2019, 13:59
I’m not submitting. Still get lift on the rear, still some parts missing.

I spent time I didn’t have on this and didn’t quite get there. Now 3 weeks out of town.

Let’s see if I can get something reasonable for race 3.
Why not submit? I'm hoping with a higher mesh fidelity my car will spring a bit more to life.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 15:06
by rjsa
It’s soooooo bad...

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 15:10
by CAEdevice
In the last two days I worked more on the CAD side than on the CFD side: the first submission may be not competitive, but I have a solid base to evolve in the next races.

Jjn: I appreciate the advanced rounds on you car. Are you modeling parametrically?

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 15:14
by jjn9128
CAEdevice wrote:
17 Aug 2019, 15:10
Jjn: I appreciate the advanced rounds on you car. Are you modeling parametrically?
Yes fully parametric.
rjsa wrote:
17 Aug 2019, 15:06
It’s soooooo bad...
Just to check you've corrected the lref error??

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 16:01
by rjsa
I did. It looked better before.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 16:15
by variante
BTW my lRef value is already 1, but the CoP is all over the place anyway.
I will race the car with a manually calculated CoP...

Also, i haven't really made any progress, downforce wise.

So, don't worry, we're all in a bad situation (aside from JJR maybe :D )

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 17:58
by rjsa
Yeah, I plowed through today with the 2 hours nap my kid took and managed a probably legal car.

Will decide rake or no rake and submit it for 2 races.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 18:02
by jjn9128
variante wrote:
17 Aug 2019, 16:15
BTW my lRef value is already 1, but the CoP is all over the place anyway.
I will race the car with a manually calculated CoP...

Also, i haven't really made any progress, downforce wise.

So, don't worry, we're all in a bad situation (aside from JJR maybe :D )
My COP is okay, but total downforce is crud. I wonder if low mesh fidelity in the fast case is hurting the performance of the floor and the efficacy of vortex structures.

Re: [MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

Posted: 17 Aug 2019, 18:38
by LVDH
I can only recommend to submit what you have. There is a small chance that there is still an issue with CoP. When I have all your cars I will get a better picture on this.
However I have seen some of them because of support questions. What I can see is that the front wing produces about twice the amount of downforce of what the rear wing achieves.
The front wing is simply much larger than the rear one and closer to the floor.
So having a front heavy car is no big surprise and most cars will suffer from this.
I am almost wondering if you guys are seeing what all F1 teams had to fight with when developing the new cars and one red team concluded to just reduce the downforce on the front wing while the others discovered that there is some kind of trick, to keep the front wing downforce while still producing a lot in the rear.

And yes, the coarse meshes do not help to keep vortex structures alive. With turbulence models, I can only do so much. I have at least added more refined mesh in the MFlow version used for this race, esp. behind the front wing.