Quote:
Originally Posted by JulianEdgar
Sorry, what has this got to do with your claimed ability to compare the drag of different cars based solely on measured centreline pressures? Are you retreating from this absurd claim?
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1) forward stagnation pressure and base pressure gives us some insight into the overall delta-P across the body. Any information is way out ahead of nothing.
2) squarebacks have no facility for pressure regain, as they offer no cross-section contraction. And we'd anticipate low base pressure, and high drag.
3) notchbacks offer some pressure regain, higher base pressure, and lower drag.
4) a streamlined fastback offers the greatest pressure regain, highest base pressure, and lowest possible drag.
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Especially if vehicles are normalized to identical frontal area, pressure profiles, even if only centerline, will give some insight into the macro-environment around the vehicle.
* Two water heaters of identical exterior dimensions, handling an identical volume of water, at equal inlet and outlet temperature, may exhibit different input energy requirements. Without X-Ray vision, one may correctly infer that, the unit with the lower energy requirement has a more efficient thermal insulation package.
* The inverse of the water heater's R-Factor, is it's thermal heat transfer coefficient, U. The greater the R-Factor, the smaller the U, and the more bang for the buck, with regards to hot water costs.
* Just as with the drag coefficient on the car.
* Delta-Ps can be a glimpse into efficiency.