Quote:
Originally Posted by freebeard
I appreciate them. Even the wrong ones. 
This is the basic question I would like answered. Vekke was no help. Dimples work, why not raked edges (cough! Cybertruck cough!)
Free and Open Source software is wonderful. Since 2.80 or so, Blender has had a Geodesic add-on. Here is the contextual menu.
https://i.stack.imgur.com/itv2a.jpg
Review the Object Types and Object Parameters. All the Platonic shapes for primitives; I'm not sure the difference between Squish and Eccentricity. You can add a Superellipse in two dimensions or all three.
Autodesk's parametric NURBs modelling is in contention with Blender's Geometry Node Editor. |
They don't work! Not on a full-scale automobile.
The only reason they're on a golf ball is because of Reynolds number. Even at 110-mph, coming off the clubhead of a driver or iron, the ball is too 'short' to achieve supercritical Rn.
Artificial surface roughness hastens the transition from a laminar boundary layer, to a turbulent boundary layer, the best thing for flow attachment and drag reduction.
The reason the golf ball has 'dimples' is that they don't stick 'out' and can't get knocked off. Sand glued to the ball would do just as well, but it wouldn't survive the rigors of of the game.
The stunt that Mythbusters pulled had to do with the crappy notchback design of the Ford. The only dimples that did any good to the Ford were the ones on the rear of the roof, preceding the top of the backlight, acting as vortex-generators, and helping with flow reattachment onto the trunklid / boot.
You cannot take the longitudinal flow on the aft-body of a vehicle and shove it sideways. You're creating the kind of pressure kink Hucho insists must be completely avoided. It's part of the fluid mechanics ground rules he hoped the readers would get from his 2nd Edition. It's 33.3% of what he hoped to get across.
I don't know anything about other editions.
------------------------------------------------------------------------------------
Please expand on what you mean by 'raked edges'. I'm not clear on what you're trying to convey.