Dusty car base areas
 

Toyota RAV 4 Hybrid:

https://i.postimg.cc/8cpFLpLP/IMG-1139.jpg

Toyota Land Cruiser Prado:

https://i.postimg.cc/KYt4VkN8/IMG-1249.jpg

Land Cruiser Prado showing interesting roof separation - airflow tripped by panel margin:

https://i.postimg.cc/CxPWgmcv/IMG-1091.jpg

And, then, on another occasion, you can see that on the same car the airflow remains attached across the upper surface of the rear spoiler:

https://i.postimg.cc/4xnM4p7B/IMG-1248-cropped.jpg

(The owner gets their car serviced at the local garage, that I walk past frequently.)

And another - very 'feathery' separation line down the side.

https://i.postimg.cc/FzydwPQz/IMG-0665-cropped.jpg

Lack of attached airflow under rear 'wing' - that's really acting as a spoiler. (Or as a partially stalled wing, I guess.)

https://i.postimg.cc/TwWC5Xns/IMG-0167-1.jpg

I have tons of photos like this of my car from the El Mirage dry lake bed here in Southern California.

In these, I like the contrast in the dust patterns between the first Toyota pic and the blue Peugeot. Seems the Toyota people got much better results for the flow along the sides of the vehicle.

EDIT: or maybe the Peugeot was traveling at a yaw angle to the wind.

Blue car is a Holden Astra (same as Opel Astra). Yes, RAV 4 hybrid is amazingly clean down the sides.

This is my favorite dust picture:

https://ecomodder.com/forum/member-f...4-hpim1176.jpg

...because it shows the various vortexes on an open wheel, Outward at the bottom and rearward at the center and top. The wheel carrying dust forward of the centerline is just icing on the cake.

Yes it's interesting, but for me at least, doesn't help at all in our modifying cars. On the other hand, dust deposition on road cars is a very powerful tool in seeing aspects such as separation lines, changing airflow behaviour on different days (eg the Prado), etc.

You have shared this photo a bunch of times, and I never regret the repeat. One of the best shots ever taken for seeing aspects such as separation lines, visualized here beautifully over the front tire and aft of the passenger compartment. You can see the recirculation zone behind the tire recapitulated behind the car and easily connect the principle to the dust sticking on the base area. Would be an excellent teaching tool. In fact, next time I am at El Mirage, I'll see if I can get still shots of dust deposits on one of the roadsters that can compare to this.