Problem $3(10$ pts$)$

A circular cylinder of diameter $0\mathrm{.}4$ m rotates at $90$ rpm in a uniform stream of $10$

m$/$s$.$ Assume that the flow can be modeled using potential flow theory.

$($a$)$ Locate the stagnation points

$($b$)$ Calculate the rotational speed when the stagnation point moves off the cylinder