Concave Vs Convex?

[Lightspeedrt]

Ok so i am going to ask a relatively open question here. In regards to making a front splitter to direct airflow around a wheel what is better to create less drag, less downforce and less lift?


Concave or Convex?
Directing airflow around or over?

Sorry if im getting a bit carried away here.

[shelly]

The best solution should be convex shape, trying to dierct the most flow to the side. See for example audi r18 for a recent implementation

[raymondu999]

Less downforce and less lift? Both are mutually exclusive. Lift is a vector quantity rather than scalar no? Wouldn't less df automatically mean more lift, and vice versa?

Maybe what you want is as close to 0/neutral lift?

[Lightspeedrt]

Haha yes sorry i know what you mean raymondu, i'm speaking for F1 in Schools so neither lift nor down-force is required but inevitably will happen, is it better if i have more lift to combat the down-force? or visa versa?

[Lightspeedrt]

There is two cars of mine i can show you, both of previous World and State championships, one includes a Front splitter directing air above the wheels, the other around. (Can't show you our current car, never know who is sniffing around)

[KeithYoung]

? CO2 car championships?

[lizatailor23]

You mean convex vs. concave well if you dont understand this as an airforce argument then i know that your technology gap. So if you are confused it means you dont understand. If you can understand then you are still miles behinds in utilizing this thinking ...yes it belongs in AIR FORCE thinking!

[MIKEY_!]

What you want is absolute minimum drag. DF is irrelevant beyond just stopping the car lifting of the tracks.

I'd go for a "bullet cut into quarters lengthwise shape" (bit of a mouthfull isn't it! ) directing air both along the sides of the car and above it. Try to minimize both surface area and cross-section as much as you can (if you weren't already).
Hope that helps.

P.S so your on the Aussie team then?

[riff_raff]

Would the airflow diverted over the top of a spinning tire make lift or downforce?

If the airflow is diverted around the outside of the tire, what happens to that airflow beyond the tire?

[MIKEY_!]

Going around the flow would be quite smooth I think (on this small scale)
Going above there would be a small DF benefit at the front of the car and some flow separation across the top of the tire. That may be useful in reducing drag but I couldn't say if it would just create eddies and such and increase drag.

Are F1 in schools teams allowed to test their designs in CFD first?

Here's what I'm thinking...
DF will be created as the air is forced upward, however as the air reaches the top of the curve it will separate or create lift.

[flynfrog]

Would the airflow diverted over the top of a spinning tire make lift or downforce?

If the airflow is diverted around the outside of the tire, what happens to that airflow beyond the tire?

mostly drag. Maybe a little lift.

lightspeed check some older threads on f1 in schools on here. There is one by baziland where he cfd test a few of the ideas you have.

[Lightspeedrt]

Thankyou for all the input guys,

@flynfrog i am good mates with brett and i have had alot of collaboration with him i have been over he's thread and still can't seem to find some of the answers i need, i have talked with brett about this and we ran some CFD on the front splitter and found directing airflow around the wheels creates less drag but more lift than one with an angled slope of 30 degrees which creates more drag but less lift. (Ill try dig up some pics and results to show you) Would it be worth running the 30 degree slope creating more drag but less lift? Lift slows the car down too right?

@MIKEY_! Can you elaborate on what you mean when you refer a "small DF benefit and flow separation" being useful in creating less drag? Wouldn't flow separation and DF increase drag?

[MIKEY_!]

The F-duct from 2010 and the wing flexing systems that preceded it seem to have used flow separation to reduce drag. Applied correctly it can result in higher top speed. The small DF benefit is really of no consequence. Like I said, so long as the car isn't getting airborne you need not worry about DF at all. Actually now that I think about it a little net lift might not be a bad thing if it reduced your rolling resistance (without loosing car control and rubbing the sides of the tracks that is!)

First thing I'd be doing is removing those wings. Unneeded DF + surface drag + drag from the vortex at the tips + extra weight + extra machining time = waste of time.

[Lightspeedrt]

Wings are required in rules and regulations, i have made them as small as possible with no AOA.

The F-duct from 2010 and the wing flexing systems that preceded it seem to have used flow separation to reduce drag. Applied correctly it can result in higher top speed.

If so, would this theory have any effect at the approx. 85km/h the cars do? Or would this be too slow for it to come into effect?

If it would come into play how could it be applied correctly to the car?

[flynfrog]

The F-duct from 2010 and the wing flexing systems that preceded it seem to have used flow separation to reduce drag. Applied correctly it can result in higher top speed. The small DF benefit is really of no consequence. Like I said, so long as the car isn't getting airborne you need not worry about DF at all. Actually now that I think about it a little net lift might not be a bad thing if it reduced your rolling resistance (without loosing car control and rubbing the sides of the tracks that is!)

First thing I'd be doing is removing those wings. Unneeded DF + surface drag + drag from the vortex at the tips + extra weight + extra machining time = waste of time.

you really should learn what you are talking about the advice you are giving is completely wrong.

The fduct only works because of the massive drag already on the car on a streamed-lined car any flow separation is going to cause more drag.

Trying to create lift to reduce rolling resistance will not result in a net gain. Any unnecessary manipulation of air to create lift is going to add more drag than it reduces in rolling resistance.