Quote:
Originally Posted by tomi_k
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From: SAE Paper 840300, by Ahmed et al. :
* The model exhibited it's highest drag at 30-degree downslope, Cd 0.378
* researchgate shows Cd 0.351- 0.365 for the same 30-degees.
* they might have kept testing until they 'proved' critical Reynolds number.
* at 30-degrees, they're in the 'forbidden zone' of bistable flow.
* the lowest drag was achieved with a 9-degree slope, at Cd 0.2298.
* with 10-degree plan-taper, and a 10-degree diffuser, the drag minimum of Cd 0.214, compared to Cd 0.25 for the initial model condition, according to Bearman et al.'s research.
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I don't know why they would intentionally choose the worst-case scenario to begin with. And the initial drag disparity is discomforting.
