Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 47: Fluctuations, Noise and Other Transport Topics (joint session TT/DY)

TT 47.13: Talk

Thursday, March 20, 2025, 18:15–18:30, H31

Vortex shedding in superfluid He-4 and in a Bose-Einstein condensate — •Wilfried Schoepe — Fakultät für Physik, Universität Regensburg, D-93040 Regensburg, Germany

Our experiments on vortex shedding from a microsphere oscillating in superfluid He-4 at mK temperatures is compared with experiments on vortex shedding from a laser beam moving in a Bose-Einstein condensate as observed by other authors. In either case a linear dependence of the shedding frequency fv=a(v-vc) is observed a above some critical velocity vc for the onset of turbulence and the coefficient a is proportional to the oscillation frequency f above some characteristic value and assumes a finite value for steady state motion f=0. An analytical relation between the superfluid Reynolds number and the superfluid Strouhal number is presented.

Keywords: Vortex shedding in superfluid helium; Vortex shedding in a Bose-Einstein condensate