Fender skirts affect on other forces ?

[jimchitas]

so i wonder if you install fender skirts what impact will have at other forces .
Firstly i know fender skirts will decrease cd (drag coefficient) but i am questioning if they can have affect on cl (lift) do they decrease lift and create downforce or they dont have a impact in other forces. i want to run this in cfd simulation but i cant have some issues.
what do you think ?

[freebeard]

i want to run this in cfd simulation but i cant have some issues.
what do you think ?

What issues can you not have? What is you CFD software? It could be run with and without skirts to give some delta figure.

'Skirt' could be anything from a half-skirt to a Jimmy Jones bubble skirt. YMMV.

[jimchitas]

i dont have any software issue my brother borrow my pc for a week so i cant do anything i also use openfoam

[freebeard]

Let us know what you find out.

[aerohead]

Originally Posted by jimchitas

so i wonder if you install fender skirts what impact will have at other forces .
Firstly i know fender skirts will decrease cd (drag coefficient) but i am questioning if they can have affect on cl (lift) do they decrease lift and create downforce or they dont have a impact in other forces. i want to run this in cfd simulation but i cant have some issues.
what do you think ?

I was without transportation for 11-days, and had time to dig around in my archive.
I could find zero references which attributed wheel skirts to 'lift' of any kind.
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Directional stability 'WAS' mentioned, as with the fully-skirted 1985 Ford Probe-V concept, in which the lead aerodynamicist reported that the car exhibited no handling issues at high speed, crosswinds or not.
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If your CFD software is capable of registering drag, lift / downforce, pitch, roll, or yaw moments, they'll show up, or not, depending on the body architecture.
If the original OEM data cloud is modified to include skirts, then, if any of these forces are altered by the presence of the skirts, they'll just be represented as new information after the post-processing data reduction. I don't see how it can be an 'issue'

[jimchitas]

i belive they have affect in other forces maybe is small or even big but still i wonder can they make downforce or just lift or they just decrease drag (which wil be ideal for future projects) lets hope my research will be accurate with numbers

[aerohead]

Originally Posted by jimchitas

i belive they have affect in other forces maybe is small or even big but still i wonder can they make downforce or just lift or they just decrease drag (which wil be ideal for future projects) lets hope my research will be accurate with numbers

We can't rule out the possibility for lift/downforce, but if it did occur, it might be only within the context of cleaner flow created, which might enhance the performance of an airdam, or rear diffuser, both clearly associated with spoiling lift, specially in high-performance sports cars.
Otherwise, longitudinal attached airflow, traveling along the sides of a vehicle, would possess no shearing vector capable of acting vertically, into the turbulent boundary-layer adjoining a vertical surface ( skirt ). Pressure could not impart a lifting force against a vertical surface. Only a yaw moment or negative roll moment.
For a typical passenger vehicle, and at normal, posted speed limits, 'lift' isn't considered to be something we'd obsess over.

[Piotrsko]

Well round window superbugs above 80mph come to mind, but that is a nitpicking point.

[jimchitas]

hahahah

[freebeard]

????

I've got a flat-screen Superbeetle and it will barely do 80. The Notchback had a five-speed and could cruise at 85.

Road & Track tested the Beetle and found zero lift in front from the rounded nose. Cal Look stance is de rigueur.

At 140 they need the dog house box on the back.


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