Lets assume that vacuum empty cylinder has a spinning top. Rotational speed at circumference is V. Cylinder axis is oriented verticaly. Cylinder is surranded by air at athmospheric pressure and weights slightly more then displaced air.(adsbygoogle = window.adsbygoogle || []).push({});

According to Bernoulli principle there should be pressure differential dp between top and bottom becuase of fluid speed difference. Bottom is stationary Vb=0, Average speed of top is Vt = 2/3*V (if I calculated correctly). This means that dp = <air density> * Vt * Vt / 2.

Question: will cylinder fly if top spins fast enough ?

-al

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# Bernoulli's spinning-top-cylinder problem

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