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Re: Khamsin Virtual Racecar Challenge 2015
Posted: 22 May 2015, 09:26
by CAEdevice
Thank you Ric, the upper crash structure should help the rear wing (see my previous post) but is a temporary solution.
The definitive solution would be similar to JJR rear wheel arches (JJR car is my favourite).
Variante developed some details and your car (Brook) looks good too.
Mantium and TF could be good outsiders.
Talno has a couple of very interesting solution (maybe the most innovative car), but at first sight it would need some more wind tunnel testing.
UPDATE: I've just received the results. Quite happy, but I can't understand the difference of 900N between my local solver (OCCFD) and the official one. It seems that the rear wing works better on my PC

Re: Khamsin Virtual Racecar Challenge 2015
Posted: 22 May 2015, 10:58
by TalnoRacing
Hi Guys,
First post on the forum, and first time competing in anything like the KVRC challenge.
CAEdevice: thank you for the kind comment. I don't have a CFD program to test my design as I have not been successful at making OCCFD work on my computer, so what you see is what I thought would work. Hopefully I can get it going soon and start refining my design.
Arno
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 22 May 2015, 11:27
by JJR
I like Talno front wheel arches - so brutal and agresive - it reminds me on Lister LMP car.
It looks like that Mantium gained a lot of downforce compared to 1st round.
TF - niceand clean design. I can imagine it will be efficient in therms of L/D ratio.
Mateo - I m glad to hear that you improved and it is strange to have different results with same software.
We are going to have much closer competition for 2nd round.
Fingers cross for everybody
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 22 May 2015, 23:16
by julien.decharentenay
@CAEdevice could the difference be explained by some difference in the wheels or suspension position? Let me know as I would be very interested to nail it down. Or it could be a difference in openFoam versions...
On my side, I have finished running the CFD models - I was a little late towards the end... Still a little to do until Sunday to release the results...
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 00:34
by RicME85
Julien, I thought I would give my input on the correlation between OCCFD and the official result, as you know I like to help with perfecting your product.
OCCFD (via AWS):

Official KVRC result:
As you can see there is a very slight change but it must be noted that the geometry has changed slightly, the pressure maps however are pretty much identical. For the OCCFD AWS run I forgot to add the mirror and there was a couple of things that needed changing after first submission and IMO these are the reasons for different results on my car.
OCCFD (via AWS):

Official KVRC result:

Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 08:11
by etsmc
Well i have more downforce than drag this time but still not enough...
Drag: 1774.47 N
Drag coefficient - Cd: 0.84
Drag area - Cd.A: 1.48 m2
Downforce: -1950.38 N
Downforce coefficient - Cl: -0.92
Downforce area - Cl.A: -1.63 m2
CoP of downforce: 1.488 m along streamwise (Y) direction from Y = 0.00 m.
KVRC Only: Corrected CoP of downforce: 1.569 m along streamwise (Y) direction from Y = 0.00 m.
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 09:29
by CAEdevice
Thank you for sharing your data. Both of you were able to increase the downforce.
It seems that different design concepts give similar results, and that performance is a matter of details.
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 10:57
by CAEdevice
A question for Variante: wich is the function of the inlets on the rear suspension covers?
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 12:42
by RicME85
CAEdevice wrote:Thank you for sharing your data. Both of you were able to increase the downforce.
It seems that different design concepts give similar results, and that performance is a matter of details.
Sure did increase downforce, this is latest races result:
and this race:

Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 12:58
by RicME85
CAEdevice wrote:A question for Variante: wich is the function of the inlets on the rear suspension covers?
I would assume engine inlet.
What I want to know is if JJR's cooling inlet is like this:

Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 13:00
by variante
CAEdevice wrote:A question for Variante: wich is the function of the inlets on the rear suspension covers?
I think you're referring to the engine inlets.
@RIcMe: impressive results. I wonder how many cars will be in that performance range this round...
BTW i'm having a bit of fun with SurfaceLIC...what a tool!! I think i can finally master vortex management thanks to it. I recommend it to you all!
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 13:33
by RicME85
Thanks, the time I spent studying your car clearly paid off
I have had a go with SurfaceLIC but couldnt get it to work despite Chris sending me a tutorial.
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 18:49
by cdsavage
Some (provisional) speed data from Monaco:
RicME85 wrote:I have had a go with SurfaceLIC but couldnt get it to work despite Chris sending me a tutorial.
If you're still interested, PM me and we can try to figure out what the problem is.
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 19:43
by CAEdevice
Impressive performance for Mantium RAY!
JJR and Variante are still the best cars. Mine (CAEdevice) seems to have some efficiency limits!
Among the others: TF new car is a big step forward.
We will see some interesting things in the "middle" DF races (I'm quite worried about JJR efficiency and Variante evolution).
Re: Khamsin Virtual Racecar Challenge 2015
Posted: 23 May 2015, 20:39
by machin
I managed to find some internet reception to see how its going... Awesome... Those Apex Speeds being the Massenet ones if anyone is interested... Looking good... Should be a nice tight fight again... Looking forward to seeing the results!