Thank you for posting the video.
Is this thicker boundary layer air responsible for mitigating or jumping over the different angle between rear window glass and trunk on a saloon/sedan?
This intersection is usually accused of interrupting attached flow, however in wind tunnels with smoke the flow looks smooth, angle differences seem to disappear - especially with increased distance from surface.
Where are the greatest pressure differences measured at the rear of the car?
1. Between top and bottom
2. Between top and side
3. Between side and bottom
Only 4-planes of interaction on a rectangular section car/truck, correct?
I suspect the "Jet Pump" phenomena is greatest under the car where it is squeezed and partially contained by ground plane.
I have not read the PDF in the link below, but it could be related to this topic.
Review on Aerodynamic Drag Reduction of Vehicles
https://www.researchgate.net/figure/...fig1_330661575
