trying to understand 'supra' TRD style vented fender

[DAEMANO]

Originally Posted by MisterSheep

The amount of stupidy in this thread...

But OP great questiong and my answer is idunno. But would love to know if theres actually an answer.

Actually @Gunman answered the question correctly just a few posts above.

Originally Posted by Gunman

The high pressure in the wheel house, will be higher than the flow along the body, and the air will move from high pressure to low, seeking equalization

[continuecrushing]

I would certainly think so

[mav1178]

Originally Posted by Gunman

The high pressure in the wheel house, will be higher than the flow along the body, and the air will move from high pressure to low, seeking equalization.

Assuming the car has no fender liners.

For any fender vent to work, there has to be an inlet for air to pass in from. If there isn't (or if the stock fender liner is left intact), there is no use for this other than cosmetic.

-alex

[mav1178]

Originally Posted by Top-Secret

And I started to focus on high pressure build up in the wheel wells and how it *could potentially* cause lift.

I think to understand one you must look at the overall picture.

"Lift" in the wheel well, sure, but what is the overall aero balance? If having a bit higher lift in the wheel wells via enclosed fenders w/ liner yields better overall aero balance in the front end overall, I'll take the small tradeoff and find downforce elsewhere (canards, splitters, both, etc).

I enjoy watching sports car racing because top teams always try to find ways to improve aerodynamically. To have a functional vent you must always have a way to feed the vent...

Some samples:
http://www.mulsannescorner.com/newsmarch15.html

-alex

[Kiske]

The air coming into the wheel well and inder the car tends to be of a higher velocity and lower pressure. When it meets the spinning wheel volume of air it is diffused. That airflow loses velocity and increases in pressure.

I'f In not mistaken, it isn't the high pressure causing lift but, the LOW pressure on the backside and top of the wheel. This is why the tops of fenders are louvered and the rears aren't as wide as the front on widebody fenders or the rear section is vented... to get air out of the fenders as efficiently as possible.

One of the reasons for lips and front diffusers to have the little wing's infront of the wheel well it to help direct air not moving along the body away from the high pressure zones.

Again, no expert.

Feel free to become one. You gonna need some time to get through it all.

http://ltces.dem.ist.utl.pt/lxlaser/...apers/15_1.pdf

http://www.ara.bme.hu/~regert/public..._corrected.pdf

http://www.ara.bme.hu/~regert/public...s_cmff2003.pdf

http://www.atzonline.com/index.php;d...lloc=3/id=8005

[CrispyCheddar]

bro, you got a voicemail

[Top-Secret]

good thing i have nothing but time at work. thanks for the links. ill keep reading into it more

[Gunman]

Originally Posted by Kiske

I'f In not mistaken, it isn't the high pressure causing lift but, the LOW pressure on the backside and top of the wheel.

6 of one, half dozen of the other. The pressure delta is the key, and as long as the pressure in the wheel house is higher than that going over the top of the fender, venting it will create downforce, aka reduce lift.

You're venting air, and turbulence created by the rotating tire, "tire squirt" behind the tire, air from bead blowers, and other fans, and air being extracted from front diffusers. The more you get out of the wheel house, the better all those things work.

If you look at this GT-D/GT3 Viper, the side cove has a passage from the wheel house, to allow air to exit from behind the tire. This is the same on the GTLM version. But, the GT-D/GT3 also has vents above the tire, for even more downforce.


Note no vents on top of fender, this is the GTLM (Lemans) spec car:


But GT-D (and GT3) has the top of fender louvers:


Note, I use the Viper as example, since I am most familiar with that GT car.