There are NUMEROUS journal articles on crosswind stability for all manner of vehicles; unfortunately the vast majority are pay-walled (~ $30 each to read them) and my interest does not extend that deeply. I agree with the points you make.gruntguru wrote: ↑Sun Jun 14, 2020 6:39 pmYes a big lump of foam and some tape. My money says it will make no difference.
There is a list of drag coefficients here https://en.wikipedia.org/wiki/Drag_coefficient no side-on coefficients for cars unfortunately but a parachute (i3 side panel?) is about 1.3, same as a flat plate.
Another thought. This car has a very low centre of gravity so it is likely the suspension has quite low roll stiffness and low roll centres. This would allow the body to roll more in the presence of cross winds.
The BMW i3s sits lower, runs lower profile tyres and stiffer suspension. You could investigate upgrading to some of these parts. IMO stiffer sway bars would be the best option.
My "feeling" or hypothesis is that if the concavity was changed to an even surface or (better) a curved convex surface that the stability would improve. It is something that "jumps out" to the observer. I suspect that breaking or disrupting the surface of the paneling was a marketing or styling move to avoid a panel van or SUV look.
https://en.wikipedia.org/wiki/High-speed_rail You can see many high speed rail coaches and, flat panels yes, concave panels no.