Quote:
Originally Posted by freebeard
Citation? Or are we talking about Thee Holy Template?
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1) The thread was presented as an alternative 'template' to the ASTs.
The aerodynamics of the sphere is so well known that, it's measured drag can serve as a calibration for Reynolds number.
2) If an analog 'clock face' is superimposed on the image of a sphere, in side elevation, and 'flow' is attacking from the 'left', we already know what the flow is doing, whether in a laminar boundary-layer ( LBL), or turbulent ( TBL ).
3) The forward's stagnation point will always be 3:00 O'clock.
4) With LBL, the flow will separate near the 11:00 O'clock location, before the flow ever reaches the maximum cross-section of the body.
5)'Dimpling' just the leading edge of a smooth sphere forces an immediate transition to TBL, which, without going into boundary-layer theory, has the facility to survive positive ( adverse ) pressure gradients that would trigger flow separation in a LBL.
6) With the dimpled golf ball, coming off the face of a club head @ 110-mph, the flow separation is moved from 11:00 O'clock, rearwards to 115-degrees behind the forwards stagnation point, adding pressure recovery, a smaller wake, of higher base pressure, lower total drag, greater distance off the tee.
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7) If you project a horizontal line from the new separation point, to the left, until it intersects a vertical line down from the 12:00 O'clock position, you've isolated an oddly-shaped 'pie-piece,' that can be used as a template for streamlining.
8) You'd 'double' the image, in mirror-image ground reflection, introduce whatever ground clearance you chose, leaving the separation point at the road interface.
9) Add a 'nose' and you have a separation-free shape.
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10) It will be 'longer' than the ASTs, so the friction drag will be amplified, but it will be free of pressure drag.
11) I've flown over London, but have never 'been' there, so I don't know how Big Ben actually is, but it's face would probably be large enough to create one of these crude templates for cars and light trucks. It's aerodynamics is a 'known quantity'.