Aerodynamics and the origin of parasitic drag Ewald HUNSINGER - Michaël OFFERLIN.
Within the framework of a phenomenology of aerodynamics, specifically developed to put an essentially experimental science back in its true place, we were led to examine in the first part of this study, the effects that could have on the flows, the phenomenon of the viscosity of fluids in general and of air in particular. We have thus described the experiments which had been imagined to highlight not only the viscous phenomenon, but also the tangential forces which resulted from it and especially the phenomenon of the boundary layer of which so many people speak even though the blur in which it is. left behind is the source of so many misunderstandings.
We have also seen that significant variations in the coefficient of friction depended on the quality (laminar or turbulent) of this boundary layer and that the laminar / turbulent transition took place at a Critical Reynolds Number of approximately 500, a number which was constant, at least in the case of the flat plate and obviously in the absence of any disturbance.
Before examining what happens when one "inflates" this flat plate to transform it into a "profile", it is also advisable to note all the advantage that there is to be gained from these flat plates from the very fact that they make it possible to isolate the effects and consequently obtain pure phenomena, more easily quantifiable.