[kach22i]

Originally Posted by RWebb

you should talk to Dr. Ed E. Size about the degree of roundness that is aerodynamically allowable

Who?

This is what I mean about round rear corners that not do not allow for clean detachment of air.

Kármán vortex street
https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_vortex_street


Drag of a Sphere
https://www.grc.nasa.gov/www/k-12/airplane/dragsphere.html

Case 3 shows the flow as velocity is increased. The downstream vortices become unstable, separate from the body and are alternately shed downstream. The wake is very wide and generates a large amount of drag. The alternate shedding is called the Karman vortex street. Here is a computer animation of the shedding, with the flow going from right to left.

This type of flow is periodic, it is unsteady but repeats itself at some time interval. The pressure variation associated with the velocity changes produces a sound called an aeolian tone. This is the sound you hear when the wind blows over high-power wires or past tree limbs in the fall or winter. It is a low frequency (low pitch), haunting tone.

The Audi White Noise Concept Is an Electric Vehicle With a Snarl
https://hypebeast.com/2016/4/audi-white-noise-concept



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