Quote:
Originally Posted by Joggernot
Cd's post on another thread caused me to think 
Let's do a different think...
The back of a pickup is a cavity; the bucket headlight is a cavity. The pickup's least resistance is with the tailgate up which allows the air to form a ball in the bed of the pickup, around which the air flows with least resistance.
The bucket headlight perhaps acts like the bed of the pickup, but on a smaller scale. A ball forms in the bucket and the air flows around the ball with least resistance.
Does this make sense to anyone else?
My best skills were used on the illustration...  |
They both create a 'phantom' effect, but I'd want to mention some qualifiers.
1) up front, all the air 'attacking' the forebody is within a 'favorable' pressure gradient. It's all flowing towards a region of lower pressure.With just a bare minimum of edge radii, the air will flow around the front as if perfectly streamlined.
2) in the aft-body of the pickup, there's an airtight rear-facing step which both triggers flow separation, and creates the iconic captured-vortex when the tailgate is closed.This vortex doesn't exist in the front, 'over' the headlight bucket. There's just dead air pooling ahead of the entire nose,creating the 'phantom' pointed nose, as illustrated in Lanchester's streamline body of revolution, 1907.
You can see it taking form ahead of Kamm's K-car of circa 1937
https://ecomodder.com/forum/member-a...-kamm-back.jpg