Aerodynamics and the origin of parasitic trails Ewald HUNSINGER - Michaël OFFERLIN.
Within the framework of a phenomenology of aerodynamics, specifically developed to put an essentially experimental science in its proper place, we were led to examine in the first part of this study, the effects that could have on 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 while the blur in which it is left behind is the source of so much misunderstanding.
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 we "inflate" this flat plate to transform it into a "profile", we should also note all the advantage that there is to draw from these flat plates by the very fact that they make it possible to isolate the effects and consequently to obtain pure phenomena, more easily quantifiable.