Quote:
Originally Posted by gRed04
Great explanation on this! One question as the spoiler is actually disrupting air flow how is that lowering cd? I would think any object side mirror or solid spoiler would negatively affect airflow because of additional drag.
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Hi,
Well in aerodynamics, all things are pretty much a trade-off. You're quite correct that the spoiler would cause additional drag. But, a couple things:
The spoiler isn't necessarily
in the airflow (I can't be certain of this not having any actual Wind Tunnel Data on it), but, it does sit pretty low on the rear. Although as you say, it very well may add some Drag.
But, the AirFlow (due to the Negative Pressure it generates) may add even more Drag, so the overall effect of the Spoiler is to reduce the total Drag on the system resulting in a net overall lower Cd.
Another Real-World example of this are the Wingtip Vortex Generators you now see on several Commercial Aircraft. They generate a vortex which is very Drag Inducing, but they help more than they hurt by containing the air on top of the Wing which wants to flow off the outside edge interupting Laminar Flow (which creates Huge Drag Penalties), resulting in lower overall Drag.
I studied Aerodynamics in School many years ago (BS, MS), but computer modeling was such, that these things were, at that time,
undiscoverable. Since then, Computers have advanced the science tremendously.
Happy Motoring!...Jim'99