Originally Posted by onehundred80
A car at speed is an airfoil, the pressure on top of the car is less and the air under it is greater. This lifts the car, you analogy is upside down. So maybe in Australia your principle works.
The air under the car is faster than the air over it.
Race car designers have worked on the under sides of the cars to get a lower pressure under the car than on top, but normally it is the reverse. The Mercedes car ad in a tunnel, if true, would rely on these forces.
Dave, you are an aeronautics engineer so I must respect your wisdom here . However, two questions arise.
If lift is created on the top of the rear deck how is the pressure less on the underside? Secondly, we all have seen how a wing creates lift. Does not a car's shape do the same?
Therefore the pressure under the car ought to , by logic, be greater than that going over the car. Hence the need to find aerodynamic ways to create downforce,; ie Wings and spoilers.
Finally, airpressure will almost always be greater under the average shaped car (which the Crossie most certainly is). Therefore will not the pressure wave create a positive air pressure bubble under the Chassis? Unless of course it is diverted to the outside of the wheels and chasis footprint.