Amateur Aerodynamics

In my previous spoiler testing, which was extensive, I made a lot of mistakes due to the fact that I only had a little education in engineering. Specifically, there were two major issues that I now want to correct: I did not normalize pressures (that is, turn them into dimensionless values for easier comparison), and I tested at only one Reynolds number. Because of these issues, the results aren’t really generalizable and are not easy to interpret. Let's fix that. Production spoilers are often art as much as—or more than, given how much styling sometimes dictates their shape—functional devices. This Toyota 86 has a very aggressive spoiler design for a production car. Recap   One of my most-read posts here has proven to be an article on spoilers I wrote early on, back when I didn't really know anything yet since I hadn't formally studied aerodynamics. I got the criticism of online theory right (yes, that weird theory that spoilers create "ideal" streamlines—w...

The study of aerodynamics is complicated. If anyone tries to tell you otherwise, run the other direction—it’s a sure sign they don’t know what they’re talking about.   Over the last two years especially, my thinking about aerodynamics and appreciation of its complexity has changed dramatically—a result of my going back to school to get another bachelor’s degree, this time in aerospace engineering where a good working knowledge of airflows is required and education in not just general fluid mechanics but also aircraft aerodynamic design forms a core part of the technical curriculum. I'm in the midst of my last semester now and to clarify my thinking at this point I decided to put some things in writing in the hopes they might help someone else as well as myself, specifically focused on car aerodynamics. A word of warning: I've tried to minimize the amount of math below, but some mathematical relations are unavoidable if you want to build an understanding of fluid flows. If anyth...