[Cd]

What is this an example of ?
It appears as if the boundary layer is attached all along the sides of the vehicle, and becomes seperated even for these rivets, which protrude pehaps 4 millimeteres.
I was under the impression that airflow remains turbulent and unattached along the skin of a vehicle.
Not being doubtful, but rather inquisitive what I am seeing here.

( After looking at the photo again, I realize that this area would be in turbulent flow anyway, because the wheel is directly in front of this area .)