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Old 04-22-2020, 06:12 PM   #25 (permalink)
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Originally Posted by aerohead View Post
General Motors explored moving-floor wind tunnels in the early 1950s,and reported that the variability of drag data,as a function of the moving wheels was statistically insignificant,and the difference could easily be compensated for during static wheel testing,deeming the extra trouble not worth the effort as far as cost/benefit/accuracy.
As to the underbody flow,I'm unsure where the disconnect would be,compared to contemporary facilities.They were suctioning the tunnel floor,to prevent boundary layer buildup,which appeared to be the sole concern.'Windage' effects of rotating tires to wheelhouse and underbody flow had been explored.
I am sorry, but are you seriously suggesting that wind tunnel testing of wheel drag, performed on a 1982 car without its wheels turning, is somehow relevant to modern cars?

Wind tunnels now test cars with a moving floor and spinning wheels. They do this for good reasons. I think this is probably the major reason that the research results have changed so much over the last decade or so.

The airflow patterns under a rough underside car like a 1982 Trans Am Firebird would be completely different to any modern car. The latest tech papers show that car drag can be influenced by how the wheels and under-car airflow interact.

I also note that "Index of Phil Knox Aerodynamic Seminars & Mod-data lists,under, Mod-data Lists: #7", as far as I can see, largely references material from the 1960s. As I said, old info is always interesting, but to apply it to current cars, when in fact current tech papers disagree, is in my opinion, not wise.

Last edited by JulianEdgar; 04-22-2020 at 06:23 PM..
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