Jase T Posted November 9, 2020 Share Posted November 9, 2020 I have to say i love physics. Watch and enjoy 1 Link to comment Share on other sites More sharing options...
old man emu Posted November 9, 2020 Share Posted November 9, 2020 The good Professor says he is demonstrating of Bernoulli's principle, but this is incorrect. At 9:27 in the video he is demonstrating the Magnus Effect. It is not the velocity of the air, bit its viscosity - assumed to be negligible in Bernoulli's principle - that is central to understanding the magnitude of the force. When a body (such as a sphere or circular cylinder) is spinning in a viscous fluid, it creates a boundary layer around itself, and the boundary layer induces a more widespread circular motion of the fluid. If the body is moving through the fluid with a velocity V, the velocity of the thin layer of fluid close to the body is a little less than V on the forward-moving side and a little greater than V on the backward-moving side. This is because the induced velocity due to the boundary layer surrounding the spinning body is subtracted from V on the forward-moving side, and added to V on the backward-moving side. If the spinning body is regarded as an inefficient air pump, air will build up on the forward-moving side causing higher pressure there than on the opposite side. This video explains it well. By the way, the Good Professor ignited my love of Science. I remember watching his "Why is it so" program on the ABC. https://www.abc.net.au/science/features/whyisitso/about.htm#about 2 Link to comment Share on other sites More sharing options...
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