Originally Posted by
echappist
^^
gotcha. Thanks.
Which brings up the next question: what is the assumed velocity in the drag force part of the equation? Every manufacturer interested in aero publishes nice look graphs of drag force vs yaw angle, but rarely do they mention the assumed relative wind speed.
The reason why i'm asking this is that FLO is apparently coming out with aero wheels that are around $800 for the pair and uses aero shaped rims.
This can get confusing and often the wheel manufacturers get it wrong. The "speed" should be the presumably uniform wind speed relative to the wheel in the far-field, the drag force is in the direction of the far-field wind, and the lift force is perpendicular to the drag. Too many times the wind tunnel results are given with the "drag force" parallel to the wheel, but in yaw this is not the drag force. Instead it is the component of the aerodynamic force parallel to the wheel. It probably is the force component of greatest interest to a cyclist, however.