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Old 01-24-2017, 01:52 PM   #11 (permalink)
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Quote:
Right?
No. There are pronounced jets the exit between the front of the tire and pavement, perpendicular to the direction of travel.

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Old 01-25-2017, 09:07 AM   #12 (permalink)
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I'm looking for a GIF or CFD still of the pressure and air flow of a car tire in a wheel well.

All I found is some related stuff so far.

AERODYNAMICS OF A SOAP BOX WHEEL
Aerodynamics of a Soap Box Wheel

Quote:
The aerodynamic behavior of a derby wheel is important because four wheels rotating at high angular and linear velocities disturb a lot of air. The amount of energy required to move anything through air increases in value by the third power of the velocity of the object. (Not to be confused with the increase in drag - Drag increases with the square of the speed.)
Yokohama Puts Spoilers on Tire Sidewalls for Better Aerodynamics
Yokohama Puts Spoilers on Tire Sidewalls for Better Aerodynamics


EDIT-1:
Some very nice cartoon-like graphics in this link below, the side view mirror one is awesome.

http://www.buildyourownracecar.com/r...cs-and-design/

EDIT-2
http://pulpaddict.com/tag/lap/

Quote:
The image on the left, taken from Jacques Heyder-Bruckner‘s PhD research on wing-wheel interaction, vividly illustrates how the time-averaged image (top) smears away much of the structure associated with the breakdown of a front-wing endplate vortex (bottom).
Source of the above:

The aerodynamics of an inverted wing and a rotating wheel in ground effect

http://eprints.soton.ac.uk/207263/

You can download the doctoral PDF from the link above. It's open-air with wing stuff, not enclosed wheel stuff.

page 33
Quote:
1.2.2 Wheel Aerodynamics
A wheel is a bluff body and as mentioned above, 40% of a Formula One car's drag is
produced by its wheels. The ow behind bluff bodies is known to be unsteady and to
exhibit strong three-dimensional properties [19]. Racing car wheels have the added com-
plexity of rotation, which makes experimental measurements that much more dicult.
Also, the wheels deform considerably under load, their temperature changes and this
would a ect the ow around it. The experimental and computational studies of the ow
around an isolated wheel are reviewed below and it can be noted that there has been an
increase in the research of wheel aerodynamics in recent years
Go to the source to read it, a bunch of missing letters when doing a Copy&Paste.
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Last edited by kach22i; 01-25-2017 at 09:30 AM..
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Old 01-26-2017, 06:02 PM   #13 (permalink)
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Quote:
Originally Posted by Frank Lee View Post
Re: Road spray



I called MNDoT with my concerns but haven't heard back yet.
Gave MNDoT a week to gather their thoughts and called 'em back just now.

They have bought into a "Towards Zero Deaths" paradigm and if centerline rumble strips reduce head-on accidents by "up to 40% AND SAVE LIVES" then that is what they are "pro-actively, systematically" gonna do, regardless of the downsides of increased road debris/spray kick-up, noise, cost, and pavement degradation.

At least I got those concerns on the radar now; the spray/kick-up thing WAS NEVER A CONSIDERATION. At. All. Before now.

They did pay a bit of lip service to pavement degradation but claim it's inconclusive as to whether water-retaining divots diminish pavement life or not. Well, time will tell on that one.
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Old 01-26-2017, 08:33 PM   #14 (permalink)
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We have the rumble strips here but not the problems you seem to have. Hard to tell from the photo but I think ours are closer together. Back in the '70s the SAE Journal had a paper on truck splash fenders. The sides of the fenders were about four inches and the rear section tapered like a ramp. Never saw them on the highway.
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Old 01-26-2017, 08:58 PM   #15 (permalink)
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MNDoT admitted that some contractors cut their divots more than 2x design depth!

Yep they are aggressive.
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Old 01-27-2017, 01:04 AM   #16 (permalink)
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Quote:
Originally Posted by Frank Lee
Re: Road spray (worthy of it's own thread)
I think it is instructive of how the wheelwell turbulence is handled. I've seen some trucks on the freeway in the rain that apparently have an 'anti-curtain' that is sucking a jet outward for a foot from the whole opening.
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Old 01-28-2017, 08:32 AM   #17 (permalink)
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The divots are great for what they are designed to do. Same as highly reflective striping. Roads are far better than fifty years ago. Try a windy day and an unruly vehicle.

Now, on the subject of too many road signs, I'd be inclined to agree.

The "curtain" is sure interesting.
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Old 01-28-2017, 10:06 AM   #18 (permalink)
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Those divots are annoying and they absolutely do result in some shortening of pavement life, especially in the northern states. On Highway 30 in Oregon, between St .Helens and Astoria, the fog lines appear to be a machine formed paint with high frequency shallow grooves. It is unmistakable when you wander onto them.
My chihuahua cross dog is hilarious with road bumps. She sits up on the console, and if I hit a turtle or anything like that her radar ears perk up and point right down at the floor, and then she jumps down by my wife's feet to go check it out. EVery time!
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Old 02-18-2017, 10:48 PM   #19 (permalink)
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Quote:
Originally Posted by Frank Lee View Post
Quote:
Originally Posted by freebeard View Post
Now if they could just get the wheel up behind the aircurtain so it does some good...
Does anyone have an opinion regarding using vortex generators on the outside of the leading edge of the wheel well, in lieu of air curtains?

It may not help on this F150, but on a vehicle where the leading edge and the trailing edge are on the same plane, i don't know why that would not help the aero.
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Old 02-19-2017, 09:51 AM   #20 (permalink)
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There is some discussion at 4:30, here:

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