[donee]

Hi All,

I am really starting to think the 2010 Prius has flow seperation issues, in comparison to the 2nd Gen (2004 - 2009). They lowered the rake of the front of the car significantly. The front to back dimension under the hood is much bigger.

I just do not get the coast down performance I was getting from my other car (if you have not heard, my 2006 Prius was totalled by an un-trained SUV driver - lets make SUV drivers pass special training and testing! - and I am now driving a 2010). Even though the low-speed rolling resistance seems just fine, maybe even better! Yea, the car is bigger, but its also a little heavier, and yea its got those big rear-view mirrors, but they have been aero-improved with steped down rim along the back. The 2010 has a nice difuser treatment under the rear bumper. It should be a wash.

On Boundary layers, I think allot depends on vehicle shape. An aero vehicles will have a thin boundary layer, and a bluff body car will have a turbulent boundary layer. So, I think the boundary layer can probably vary by a factor of three from car to car. The thickness of the boundary layer is dependant on the tubulence energy within the air next to the vehicle. Aero-experts does this sound right ?