A reappraisal of why aspirating pipes do not flutter at infinitesimal flow

In an earlier Brief Note, in 1999, a simplified analysis was presented to show why aspirating pipes-a problem related to Feynman's aspirating rotary-sprinkler quandary-do not flutter at infinitesimally small flow-rates. Recently, however, it has become clear that this earlier work is at best incomplete. A reevaluation of the problem is undertaken here, with some fresh insights as to if and why flutter does not occur at low flow velocities. In the process, the equation of motion is derived by an appropriate statement of Hamilton's principle, as well as by Newtonian methods, and the work done by the fluid is computed.