LAUSR

Vortex shedding from a microsphere oscillating in superfluid $$^4\hbox {He}$$4He 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 $$f_v$$fv on $$\varDelta v = v - v_c$$Δv=v-vc is observed, where v is the velocity amplitude of the sphere or the constant velocity of the laser beam above a critical velocity $$v_c$$vc for the onset of turbulent flow: $$f_v = a \,\varDelta v$$fv=aΔv, where the coefficient a is proportional to the oscillation frequency $$ \omega $$ω above some characteristic frequency $$\omega _k$$ωk and assumes a finite value for steady motion $$\omega \rightarrow 0$$ω→0.