(KVRC) CAEdevice

Post here information about your own engineering projects, including but not limited to building your own car or designing a virtual car through CAD.
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CAEdevice
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Joined: Thu Jan 09, 2014 2:33 pm
Location: Erba, Italy

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variante wrote:Really nice model!
From the previous speculations, i thought you were much behind in terms of development... But everything seems to be as it should. Some optimization work will make your performance increase quite a lot, as i've found out from my own experience.

Overall it's the same concept i've used on my car, which i'm showing in minutes. I wonder how many others are going for this configuration. However i've decided for different solutions in some key points...I guess we'll have to wait for the first race to see how they compare...
I'm still behind! Everything can change because I'am not happy at all with the flow under floor. What is more evident (front wing, wheel cover, ...) has not such an impact on performance! I can't wait to see you car...

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CAEdevice
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Joined: Thu Jan 09, 2014 2:33 pm
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machin wrote:Yeah, that is a seriously cool (and aggressive) looking car.... I can only guess at the flow path through the front of the car (I'm not expecting you to give away any details: especially at this point in the season!) but my guess is as per below:

http://i90.photobucket.com/albums/k248/ ... 4rcibi.jpg

...which is very similar in concept to the new Nissan LMP1 that will race this year, except that your tunnels end half way along the car whereas theirs continue to the rear.

If it were me I'd be inclined to spend a little while using the fillet tool on all those sharp edges on the wheel fairlings.. but I suspect it won't make too much difference on performance at the high downforce tracks and you probably have loads of other major design ideas to try first!

Good work!
I can't see the picture because of my smartphone, but you are right, Nissan LMP1 impressed me very much.

I partially abandoned that concept because the space allowed by the rules above the diffuser is not big enough.

About the edges: I have no space to place rounda bigger than 15mm....

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CAEdevice
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I had no time to repaint the car, but this is the car leaving for the first race.
It has not been tested with OCCFD, but I'm quite sure to have gained a little amount of DF (I hope that the new rules about the corrected COP will help, considering that the car has not been refined).

The big upper front wing disappeared and the exhausts are no more blowing into the diffuser (it gives a small advantage, about 20-30kg, but now I have more freedom designing the diffuser shape).

I added some gurneys, but I found very difficult to use gurneys in compiance with the 10mm rules.
I'll probably renounce to them for the second race.

Image

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CAEdevice
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Joined: Thu Jan 09, 2014 2:33 pm
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Last consideration before the first race: the general shape of the car impacts on the results for only about 50%. Most of the DF has been obtained working on small details (not too small.. bigger/thicker than 10mm :) )

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variante
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Joined: Mon Apr 09, 2012 10:36 am
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Hey but that's a completely new car! No more mega front diffuser, detached monkey seats, and many other details...

It's a strange choice to get rid of the upper front wing, but you had your reasons for sure as that front wing seems very elegant.

Nice winglets on top of the wheel arches! ...i hope the meshing phase will be generous with such details.

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CAEdevice
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Hi Variante!
It's a strange choice to get rid of the upper front wing, but you had your reasons for sure as that front wing seems very elegant.
There is not enough distance between the two wing of the "biplane" to have a doble effect. It worked only as a directioner of the flow: I don't need it now (not a big change for high down force tracks, but important for the low/medium downforce tracks).

Every thing is at least 10mm thick, but I agree with you about meshing.
At the moment meshing is the real "bottle neck" of the whole KVRC (I could process with OCCFD only 1 geometry over 5).
With that last evolution I'm guessing a lot.

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variante
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Talking about the 10mm rule and related meshing issues: my wings, in some points, do not reach the 10mm thickness. I have tested them with Khamsin using a 5mm surface mesh, and they did seem to be reconstructed pretty much correctly.

Since OCCFD mesh settings are similar or better compared to my simulations, i'd suggest you not to worry "too much" about those 10mm.

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CAEdevice
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Joined: Thu Jan 09, 2014 2:33 pm
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Yes, except wings rear edges

MadMatt
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I like it more like this. Simpler! Also like the flow conditioner over the front wheel arch, nice touch!

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variante
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CAEdevice wrote:Yes, except wings rear edges
Not just that. For example, when the second element of my upper front wing approaches the car's centre line (ehm...got it?), goes below 10mm even in its maximum thickness zone. But it doesn't cause problems.

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CAEdevice
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variante wrote:
CAEdevice wrote:Yes, except wings rear edges
Not just that. For example, when the second element of my upper front wing approaches the car's centre line (ehm...got it?), goes below 10mm even in its maximum thickness zone. But it doesn't cause problems.
Yes, I consider wing that too.

With mesh problems I refer not to the minimum thickness issues, but to general problems I've found with snappy hex mesh and the refining iterations of OCCFD, it seems to be related to the geometry complexity, not to the "accuracy" (minimum thichness/box dimensions).

Maybe your choice to use the last year solver was the right one, but take a look to the floor height (joking...) :)

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CAEdevice
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Ready for the 5th race: just an evolution of the car used during the race inb MagnyCours (still medium-high downforce setup). The official solver (OCCFD, running on a Windows workstation) could not process the geometry, so I used a simplified model for the simulation: I hope it will work as expected anyway.

Image

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machin
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So... Shall I ask THE question then...

What are those features on the top of the front wheel arch doing...?

EDIT; if you want to give away your secret!
COMPETITION CAR ENGINEERING -Home of VIRTUAL STOPWATCH

wesley123
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I'm interested in the front wing that hits the suspension cover as well
"Bite my shiny metal ass" - Bender

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CAEdevice
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The purpose is to deviate the flow from the upper surface of the wheel cover. At same time there is a small increase of pressure on the frontal part of the fenders.

It is not a definitve solution, but it seems to partially work.