View Single Post
Old 04-23-2011, 02:26 PM   #135 (permalink)
aerohead
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 16,268
Thanks: 24,393
Thanked 7,360 Times in 4,760 Posts
force

Quote:
Originally Posted by winkosmosis View Post
I understand the Bernoulli effect, but I'm talking about a frontal surface of a car, not the roof. That's what I'm trying to explain, that the air flowing along the front side of the car and also the stagnant bubble are applying rearward force to the car.
I apologize for butting in.
*In road vehicle aerodynamics the lion's share of a vehicles aerodynamic drag,by definition,is profile drag, composed of surface drag and pressure drag.
*Nothing can be done about surface drag so we concentrate on pressure drag which is ruled by separated flow.
*Air does not independently act as a force against the front part of a vehicle.
*The drag force is primarily the pressure differential between the forward stagnation point and the base pressure of the wake.The delta-P.
*Hucho gives A.Riedler credit for the basis of rational analysis of motor vehicle aerodynamic drag from his studies in 1911,based on the non-Newtoniam physics of Prandtl and Eiffel.
*Hucho writes in his Chapter-1 that it was a very slow process getting away from Newton's 'Impact Theory.'
-------------------------------------------------------------------------
*If you will direct a high-pressure water jet into a basin of water you will notice that as the jet nears the bottom of the basin,that the jet will 'stick' to the bottom,rather than be rocketed away by the 'force.'This is a backyard demonstration of Bernoulli's Theorem which is an integral part of Impulse-Momentum fluid dynamics.
  Reply With Quote