Quote:
Originally Posted by aerohead
Take it up with Hucho. It's his quote. It's the entire premise for road vehicle aerodynamic study.
Total drag can be reduced to surface friction drag in the absence of separation.
80% - 90% of total kinetic energy can make it to the rear stagnation point on a streamlined car.
I'm familiar with diagrams. I'm familiar with context also.
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You completely missed my point. I don't know why I am bothering, but...
1. Honda Insight Gen 1 - attached flow over rear window. (Tuft test your own car if you want to take issue with that.)
2. Measured pressures:
3. Draw in the force vector for -80 on the hatch. (Pressure forces act at right-angles to the panel.)
4. Resolve the vector into lift and drag elements (use the triangle of forces - engineering 101).
5. Note that attached flow is, in the case, causing drag (and lift).
As I said, if you think that pressure drag can be caused
only through separation, you are making a very basic mistake.