Quote:
Originally Posted by 93tracerwagon
As I understand it, however, the flow at the rear of square backed bodies is largely two dimensional because there is little vorticity in the third dimension like 30 angle backed vehicle....been reading Hucho...twice. Have to just give it a try eventually.
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*Road vehicles operate in 3-dimensional flow.
*Road vehicles operate in a full,turbulent boundary layer.
*Road vehicles operate at super-critical Reynolds number.
*Numerical solutions which can predict a 3-D automotive flow must be based on the full Navier-Stokes Equation of spherical coordinate system,requiring days on a supercomputer for a single iteration.Ask Mercedes-Benz.
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The investigators who published the work on porosity haven't a clue about the real world and don't even know what they don't know,blundering ahead on preposterous assumptions which defy reality.
They didn't even get the Ahmed body correct.
Re 300,000 is sub-critical.
They're operating in a laminar boundary layer which is impossible for a road vehicle.
They don't understand separation/base pressure-induced drag.
Without powered, blown, or suctioned artificial architectures,there's nothing the porosity can contribute.
This has been known to anyone who's actually followed aerodynamics for the last 95 years.