Look again.Giblet wrote:I think that pic is playing tricks with the eyes. I can not see where that 90 degree part is on the right side.
vonkhardingfv32 wrote:Is it wrong to say the diffuser works best with non-turbulent flow through it?
Not necessarily. But this is an open system diffuser that must work at differing speeds, with differing inlet conditions, but always at ambient outlet pressure. This would require differing diffuser angles to avoid backflow. I think one must abandon the thought of laminar flow in this case, particularly with the 90° deflection at the inlet.
"Because the rules limit the height and length of the diffuser they also limit the angle of the diffuser. By using a concave style ramp approach you can form the main part of the diffuser at a slightly lower angle - this should give better separation characteristics as I understand it."
I think this visualizes an un-realistic flow pattern, given the 90° deflection at the inlet.
I don't think this theory is incorrect. We are concerned with the angle of the diffuser roof because we do not want it to stall or the flow go turbulent. Is this correct?
In principle, yes. But I don’t think it is applicable here.
What good is a "slightly lower angle" diffuser if we have to cause turbulence to get the flow to this area? This substantial angle at the throat of the diffuser is causing turbulence isn't it? We don't see shapes like this on the underside of wings do we?
Agreed
So what makes this work so well?
With so many changes being made to the cars from race to race, how do we know that the diffuser alone makes that much difference?
Brian
What am I missing here ? Speed up air flow ? I thought the whole point of the diffuser was not to speed up the air flow but to allow the faster air under lower pressure to be reintroduced more efficiently with the slower air flow around the rear of the car to limit the amount of drag ?xpensive wrote:So gentlemen, what happened to the topic, if I remember correctly someone opened this thread by stating that the diffuser was not really a diffuser at all, not in the sense that its purpose was to speed up the air under the car anyway?
Are we still waiting for the big one, to be enlighted on how it really works, which seems to be unknown outside Virginia?
I see no damage to the diffuser. Like it or not, that sharp turn is there.n_anirudh wrote:And thats the diffuser from a damaged car having gone airborne and crashed into the tirewall..Cant be serious to take that as a reference....
The Kamm tail diff is a joke right..Why would anyone want such a sharp change in the flow geometry..the diffuser is there to bleed back air to its atmospheric pressure...
and the concept of shear drag being generated on the moving road is wrong. At no instant is the road attached to create a shear drag layer.
Thanks for the info. The bottom of the DDF probably is similar, unless you can prove otherwise.godlameroso wrote:That was a 2009 car, no DDF, and it has wheel fairings.
I agree about the definition of a diffuser. The term diffuser for devices of this kind has been around for a long time. Has it become a misnomer for what the picture shows? But that’s sacrilege, I know.n smikle wrote:This would break the definition of a diffuser though. You would see massive pressure loss with this abrupt expansion.
