Quote:
Originally Posted by 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 .)
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Unfortunately this thread goes for massive complexity where there is no need to. Forget laminar boundary layer flow: as is (correctly) stated above, there is basically none over a normal car. Instead, where there is attached flow, it is in the form of a turbulent boundary layer.
In normal road vehicles, we really need to think only about two things:
1) Whether the flow is attached (airflow guided by the shape of the vehicle) or separated (airflow not guided by the shape of the vehicle).
2) Where it is attached, the thickness of the boundary layer (with the boundary layer being where the flow is slower than the freestream), and with boundary layer thickness growing the longer the flow is attached.
Looking at the pics, my guess is that the rivets are shielding the bodywork from dirt being thrown up by the wheel, and/or the truck has brushed against something and again the rivets have protected the bodywork behind them.