Zusammenfassung
Vortex shedding from a microsphere oscillating in superfluid He-4 at mK temperatures is compared with that from a laser beam moving in a Bose-Einstein condensate as observed by other authors. In particular, in either case a linear dependence of the shedding frequency f(v) on Delta(v) = v - v(c) is observed, where v is the velocity amplitude of the sphere or the constant velocity of the laser beam ...
Zusammenfassung
Vortex shedding from a microsphere oscillating in superfluid He-4 at mK temperatures is compared with that from a laser beam moving in a Bose-Einstein condensate as observed by other authors. In particular, in either case a linear dependence of the shedding frequency f(v) on Delta(v) = v - v(c) is observed, where v is the velocity amplitude of the sphere or the constant velocity of the laser beam above a critical velocity vc for the onset of turbulent flow: f(v) = a Delta v, where the coefficient a is proportional to the oscillation frequency omega above some characteristic frequency omega(k) and assumes a finite value for steady motion omega -> 0.