Quote:
Originally Posted by AeroMcAeroFace
I think chapter 4 in Aerodynamics of road vehicles says it best
"In spite of its comparatively low drag, the passenger car is closer to a
rectangular box in terms of fluid mechanics than it is to a body of
revolution, though with refinements in aerodynamics progress is towards
the body of revolution. The flow round a car body is characterized by
separation (Figs 1.1 and 1.2) and its drag is primarily pressure drag.
Attempts to relate drag to primary shape characteristics (see section
1.2.3) have been unsuccessful. The number of parameters describing the
geometry of a car is too large and the interaction of the individual flow
fields too complex."
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I might have to agree, the last set of colorful CFD images I posed were from a PDF focusing on rounding the rear corners of the roof slope in order to reduce the chance of vortex formation.
That is to say, make the rectangular box more like the
"primary shape - Aerotemplate Part-C".
I don't recall if it is a student paper or a professional one, will check.
EDIT:
Link says SAE paper.
2011-04-12
The New Audi A6/A7 Family - Aerodynamic Development of Different Body Types on One Platform 2011-01-0175
https://www.sae.org/publications/tec.../2011-01-0175/
Quote:
Originally Posted by freebeard
Detachment is always associated to vortexes, yes no, maybe?
A vortex is just self-sustaining ordered turbulence?
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Good questions.
And what is buffeting?
I'll post some images that may lead to conclusions.
EDIT-2: Will need to specify
near wake or
far wake region apparently.
PDF download.
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAJ
More of the same here:
The Effect of Vehicle Body Shapes on the Near Wake Region and Drag Coefficient: A Numerical Study
Hayder Kareem Sakran
Published 2016
Physics
The Journal of Engineering
https://www.semanticscholar.org/pape...f846b5309b934a
Another PDF
https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAY
The angled vector represents both lift and drag.
If this is true for the rear, then negative pressures on center-line of hood up front would mean lift again and "negative drag" also called thrust.
Yes?
Did anyone ever show vector arrows for the hood?
Just assuming they did somewhere at some time.