When the evidence is not enough: on "inviscid attached" flows
I remember when some years ago I found an interesting and nice visualization on YouTube called "Inviscid Flow ovrer an airfoil", where some kind of green flow (or fluid) passes an aerodynamic/hydrodynamic shape with incidence (at a high angle of attack; AoA). Most aeronautical engineers know that under normal operating conditions (at a large Reynolds number; Re), fluid detaches near the leading edge, forming a chaotic wake downstream, leading to stall since for this particular case, the AoA is about 22 degrees (I made the measurement by a print screen in Paint and based on pixels; sorry for the lack of scientific rigor). Now the question is: is that title correct? And the answer is: Absolutely not! Video 1: Viscous fluid over an airfoil ( Re~1 ). Source: Inviscid Flow ovrer an airfoil Despite the flow in such a visualization, or even better, the fluid seems to follow more or less perfectly defined streamlines as it flows around the airfoil, similar to the shown by the Pote...