LB02 - Astracrazy

[MIKEY_!]

were those holes created with boolean subtraction (a semi educated guess from my vectorworks days)? if so rotate the blocks you used to cut the holes to a 45 degree angle from the horizontal (when viewed from the front) and angle them backwards a little. the air should be passing through the endplate holes upwards, outwards and backwards (I know that is fairly unclear). the holes should be parallel with the intended direction of airflow of course, what you have at the moment is directing the air at a 90 degree angle to the direction of travel, so air may not even enter the holes at higher speeds. It may also help if the endplates are made much thinner.

That said, I've never put a wing through CFD but I hope this is of some help

[astracrazy]

thanks. I'll give that a go.

I run a quick test without any grills (more just for my knowledge) I lost 200N of downforce. So adding them adds downforce, doing them right will add downforce and reduce drag?

[MIKEY_!]

in theory, having slots shouldn't increase downforce, quite the opposite in fact, however airflow could be interacting with the cutouts behind the wing and somehow creating extra downforce... maybe

[astracrazy]

what effect for downforce/drag does the shapesof the endplate behind the main planes? i.e red bull have very minor swoops down, where macca see so have very bold curves.
http://www.f1technical.net/gallery/2012 ... /rb8-mp427
you can see what i mean there

[MIKEY_!]

as i understand it the top edge of the endplate (above the wing) generates a vortex as does the cutout behind the wing. They rotate in opposite directions so when they meet they cancel out, thus reducing drag. However they serve a useful purpose in 'sealing' the different pressure zones around the wing (to the sides, above and below) from each other. The angle of the cutout behind the wing probably influences how soon the two vorticies interact, the strength of the lower vortex and the strength of the resultant vortex on each side of the car. A steep angled cutout (like mclaren) probably makes for a strong lower vortex which interacts with the upper vortex close to the endplate, while the red bull's less aggressive one would create a weaker vortex which interacts with the upper vortex further downstream, thereby creating the sealing over a larger distance.
Of course this is just my understanding of the way it works, I would be very interested to see how it plays out in some CFD.

[astracrazy]

thanks for your help. I'll look for the difference and obviously post updates here

[astracrazy]

I've been re-doing my rear wing and doing test on it and i've got something which i dunno why its happening or how to solve.

I'm at work so no pics, sorry.

The wing is loosing pressure on the flap on each corner/edge closest to the end plates (end plate design is basic at this stage, no cut outs etc.) and i don't know why. i.e the whole flap is red, except close to the end plate which turns to blue.

Is this normal, or why is it happening?

If needs be, i'll post pics tonight.

[slimjim8201]

The high and low pressure "hot-spots" you see in several places, notably in the location you have pointed out, similar locations on the underside of the wing, and on the vertical side panels of the end plates immediately downstream of their leading edges are a result of the meshing technique utilized in SW. This effect can be seen in other CFD packages as well, but it's often evident when using a cut-cell, non-conformal mesh. In these areas, the mesh technique is not doing a stellar job of accurately representing the supplied geometry at the current resolution. Local refinement will alleviate the issue.

[astracrazy]

ok thanks