|
And to add to the discussion, I think that in road cars, vortices don't have a lot to do with how diffusers work! My tuft testing and pitot tube measurements seem to confirm that.
Diffuser effectiveness in reducing lift can on road cars can easily be explained by looking at the vector force direction as the attached flow curves upwards.
Think of the same process occurring, but this time on the upper surface of the car, eg over a curved rear hatch (so of course giving lift not downforce). Now make that upper surface have a massive pressure drop, such that flow wraps around from the side to the top surface, so creating strong vortices. Clearly lift will increase a lot. But so will drag! Drag doesn't matter much in racing cars, but concerns us.
This is one reason I don't like much looking at race car aero when talking about road cars.
|