Prevailing winds here have been mainly W-E this past week, while my commute and an extra trip I took this weekend were N-S, which got me thinking about yaw angles and car aerodynamics.
Manufacturers of time trial/triathlon bikes test their bikes in wind tunnels, usually releasing drag figures not as Cd measurements, like cars, but as total grams of drag (I was traveling to/from a duathlon a couple hours away, so my bike was in the back of the car, which was the instigation of my thoughts). It's quite easy to find tests by various companies of their own bikes and the competition, with or without riders (or dummies), water bottles, cables, etc., and all of unknown veracity (since they're used as marketing tools, and generally show whatever company conducted the test in the best light). But these tests universally demonstrate something interesting--drag decreases from 0 degrees wind angle out to around 10-15 degrees, and then begins to increase. Here's one test by Cervelo (with a dummy rider) of several different bikes:
(Not surprisingly, the solid red line is their current range-topping model, the P5).
Another, this one by Trek:
(Again, here the Trek SC "wins").
So, I wonder: is this effect seen on cars as well, a reduction in total drag at low yaw angles? Do car manufacturers consider yaw angles in their designs and testing? Is there any way to improve or tailor an existing car's aerodynamics to better handle higher or lower yaw angles, depending on expected conditions?
Discuss.