Quote:
Originally Posted by JulianEdgar
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. |
There's no dispute about your measurements.
Others are recording hundreds of pressure readings over the entire surface of the vehicle to ascertain the average, mean, and force vector resultants. Or simply recording the drag and lift from the strain-gauge load cells in the tunnel. And everything is normalized to SAE Standard atmosphere.
If the Insight can be Cd 0.09, and it's recording Cd 0.25, what percentage of that Cd differential would be attributed by the resultants down the centerline, versus everywhere else? That's delta- 0.16. We would need to parse it out. A daunting proposition.