Field Testing and Wind Tunnel Testing

Over the past several years, I've had the opportunity to do some wind tunnel testing with a variety of folks. On several occasions I've also had the opportunity to try and correlate the wind tunnel data to power meter based field tests.

Here's the field testing methodologies that I've tried in the past:

-flat, regression/Lim method
-indoor velodrome, caveman method
-dip/half-pipe chung method
-dip/half-pipe work per lap bootstrap method
-short laps-flat-ish work per lap bootstrap method
-long laps-flat-ish work per lap bootstrap method

It's been my experience with the data from the San Diego wind tunnel that the indoor velodrome has produced the best results when it comes to the academic exercise of matching wind tunnel data to indirect estimations of CxA based on power meter data. In windy conditons, it seems just a bit too easy to "post hoc adjust data" using stationary wind probes without high resolution data logging capabilities, in order to make things turn out the way one wants them to turn out.

The other methods (i.e, not indoor velodrome data) seem a bit cumbersome/time consuming and un-predictable/unrepeatable, in my experience (I had some pretty good calm Lim method data taken over many successive days that on average correlated very well with lswt.com data, but this process took something like a week of early morning test sessions, IIRC - man, I don't have the patience for that ;-) ).

It's my current perception (which is, of course, subject to change based on new reliable information) that many folks who distribute information all over the internets are using math models, or field testing data reduction techniques, that don't quite capture exactly what is going on - which I feel can lead to inaccurate results from an aerodynamic body axis coordinate system perspective.

So, basically, just as I mentioned in this forum thread:

"often times, it's helpful to pursue multiple, independent lines of inquiry when attacking a problem. Field testing is but one way to gain insight, and hopefully, this methodology (referring to the work per lap bootstrap/chung approach) doesn't steer folks unknowingly down a wrong path. That would be a bummer!"