The references are for covered and uncovered wheels. Could apply to mc, autos, aircraft, etc. The study of these sort of things can be adapted to various applications. However, if you can be patient, I can perhaps get some specific information on motorcycles done in the USAFA low speed tunnel(s) and perhaps some othere mc related information. I do know that the previous reference to the anti-pumping device (simplified) is correct.
You know, it is fairly easy to build a "profile tunnel" so that you can take a look at how smoke or other flow visulation tools allow you to see patterns around and through devices. You can use a regular flowbench as the signal generator or build a much more simple device.
Regards,
HB2
Snowed-in The High Country