Schoepe, W. (2013) Shedding of Vortex Rings from an Oscillating Sphere in Superfluid He-4 Below 0.5 K. JOURNAL OF LOW TEMPERATURE PHYSICS, 173 (3-4). pp. 170-176. ISSN 0022-2291,
Full text not available from this repository. (Request a copy)Abstract
The onset of turbulent flow around an oscillating sphere is known to occur at a critical velocity where kappa is the circulation quantum and omega is the oscillation frequency. However, in a small interval of driving force amplitudes F (or corresponding velocity amplitudes of few percent above v (c) ) the turbulent flow is found to be unstable. The flow pattern switches intermittently between potential flow and turbulence. The lifetimes of the turbulent phases have an exponential distribution and the mean lifetimes tau grow very rapidly with increasing driving force, namely as tau(F)similar to exp[(F/F (1))(2)]. In this work this experimental result is analyzed in more detail than before, in particular the force F (1) is identified. As a result, the turbulent drag force can be ascribed quantitatively to the shedding of vortex rings having the size of the sphere.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TURBULENCE; FLOW; ONSET; MICROSPHERE; LAMINAR; Quantum turbulence; Oscillatory flow; Intermittent switching |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Prof. Wilfried Schoepe |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 27 Mar 2020 07:50 |
| Last Modified: | 27 Mar 2020 07:50 |
| URI: | https://pred.uni-regensburg.de/id/eprint/15822 |
Actions (login required)
 |
View Item |
