Behavior of Ions and Quantized Vortex Rings of Low Energy in Helium II around 0.3°K

1966 ◽  
Vol 148 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Lothar Meyer
Keyword(s):  
Low Energy ◽  
Quantized Vortex ◽  
Vortex Rings ◽  
Helium Ii

Size of Quantized Vortex Rings in Liquid Helium II

1971 ◽  
Vol 4 (3) ◽  
pp. 1092-1099 ◽  
Author(s):  
G. Gamota ◽  
T. M. Sanders
Keyword(s):  
Liquid Helium ◽  
Quantized Vortex ◽  
Vortex Rings ◽  
Helium Ii

Nucleation of Quantized Vortex Rings by Ions in Helium II

1969 ◽  
Vol 23 (26) ◽  
pp. 1491-1495 ◽  
Author(s):  
Russell J. Donnelly ◽  
Paul H. Roberts
Keyword(s):  
Quantized Vortex ◽  
Vortex Rings ◽  
Helium Ii

Quantized Vortex Rings in Rotating Helium II

1966 ◽  
Vol 17 (21) ◽  
pp. 1088-1090 ◽  
Author(s):  
K. W. Schwarz ◽  
R. J. Donnelly
Keyword(s):  
Quantized Vortex ◽  
Vortex Rings ◽  
Helium Ii

Deflection of Quantized Vortex Rings by Magnetic Fields

1970 ◽  
Vol 1 (5) ◽  
pp. 1549-1552 ◽  
Author(s):  
V. Chiu ◽  
G. V. Chester
Keyword(s):  
Magnetic Fields ◽  
Quantized Vortex ◽  
Vortex Rings

Effect of velocity ratio on the interaction between plasma synthetic jets and turbulent cross-flow

2019 ◽  
Vol 865 ◽  
pp. 928-962 ◽  
Author(s):  
Haohua Zong ◽  
Marios Kotsonis
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Velocity Ratio ◽  
Vortex Pair ◽  
Synthetic Jets ◽  
Low Energy ◽  
Vortex Rings ◽  
Wall Region ◽  
Mean Velocity ◽  
Counter Rotating Vortex Pair

Plasma synthetic jet actuators (PSJAs) are particularly suited for high-Reynolds-number, high-speed flow control due to their unique capability of generating supersonic pulsed jets at high frequency (${>}5$  kHz). Different from conventional synthetic jets driven by oscillating piezoelectric diaphragms, the exit-velocity variation of plasma synthetic jets (PSJs) within one period is significantly asymmetric, with ingestion being relatively weaker (less than $20~\text{m}~\text{s}^{-1}$) and longer than ejection. In this study, high-speed phase-locked particle image velocimetry is employed to investigate the interaction between PSJAs (round exit orifice, diameter 2 mm) and a turbulent boundary layer at constant Strouhal number (0.02) and increasing mean velocity ratio ($r$, defined as the ratio of the time-mean velocity over the ejection phase to the free-stream velocity). Two distinct operational regimes are identified for all the tested cases, separated by a transition velocity ratio, lying between $r=0.7$ and $r=1.0$. At large velocity and stroke ratios (first regime, representative case $r=1.6$), vortex rings are followed by a trailing jet column and tilt downstream initially. This downstream tilting is transformed into upstream tilting after the pinch-off of the trailing jet column. The moment of this transformation relative to the discharge advances with decreasing velocity ratio. Shear-layer vortices (SVs) and a hanging vortex pair (HVP) are identified in the windward and leeward sides of the jet body, respectively. The HVP is initially erect and evolves into an inclined primary counter-rotating vortex pair ($p$-CVP) which branches from the middle of the front vortex ring and extends to the near-wall region. The two legs of the $p$-CVP are bridged by SVs, and a secondary counter-rotating vortex pair ($s$-CVP) is induced underneath these two legs. At low velocity and stroke ratios (second regime, representative case $r=0.7$), the trailing jet column and $p$-CVP are absent. Vortex rings always tilt upstream, and the pitching angle increases monotonically with time. An $s$-CVP in the near-wall region is induced directly by the two longitudinal edges of the ring. Inspection of spanwise planes ($yz$-plane) reveals that boundary-layer energization is realized by the downwash effect of either vortex rings or $p$-CVP. In addition, in the streamwise symmetry plane, the increasing wall shear stress is attributed to the removal of low-energy flow by ingestion. The downwash effect of the $s$-CVP does not benefit boundary-layer energization, as the flow swept to the wall is of low energy.

Motion of charged vortex rings in helium II

1991 ◽  
Vol 67 (18) ◽  
pp. 2505-2508 ◽  
Author(s):  
David C. Samuels ◽  
Russell J. Donnelly
Keyword(s):  
Vortex Rings ◽  
Helium Ii

STUDIES OF THE ENERGY SPECTRUM AND THE WAVE FUNCTION FOR LOW ENERGY EXCITED STATES IN LIQUID HELIUM II

2007 ◽  
Vol 21 (21) ◽  
pp. 1383-1390
Author(s):  
DE-HUA LIN ◽  
PING ZOU ◽  
ZHONG-WEI ZHANG ◽  
HONG-LEI WANG ◽  
JUN PAN ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Energy Spectrum ◽  
Liquid Helium ◽  
Excited States ◽  
Low Energy ◽  
Large Wave ◽  
Helium Ii ◽  
Wave Numbers ◽  
Specific Temperature

In this paper, we study the elementary excitations and energy spectrum proposed by L. D. Landau in liquid helium II. On the basis of the energy spectrum for the phonons and rotons, we put forward a uniform expression of energy spectrum in liquid helium II, which is limited in a specific temperature range. By using the wave function for low energy excited states proposed by R. P. Feynman or the modified one proposed by Feynman and Cohen, it can be found that the estimated energy spectrum is quite different from the experimental data, especially for the region with large wave numbers. By proposing an improved form for the wave function, we re-analyze the energy spectrum in liquid helium II, and our results show a better agreement with the experimental data.

scholarly journals Communication: Nucleation of quantized vortex rings in 4He nanodroplets

2014 ◽  
Vol 140 (13) ◽  
pp. 131101 ◽  
Author(s):  
David Mateo ◽  
Antonio Leal ◽  
Alberto Hernando ◽  
Manuel Barranco ◽  
Martí Pi ◽  
...  
Keyword(s):  
Quantized Vortex ◽  
Vortex Rings
Sign in / Sign up

Export Citation Format

Share Document