31,732 research outputs found
Resonance enhanced turbulent transport
The effect of oscillatory shear flows on turbulent transport of passive scalar fields is studied by numerical computations based on the results provided by E. Kim [Physics of Plasmas 13, 022308 (2006)] . Turbulent diffusion is found to depend crucially on the competition between suppression due to shearing and enhancement due to resonances, depending on the characteristic time and length scales of shear flow and turbulence. Enhancements in transport occur for turbulence with finite memory time either due to Doppler or parametric resonances. Scalings of turbulence amplitude and transport are provided in different parameter spaces. The results suggest that oscillatory shear flows are not only less efficient in regulating turbulence, but also can enhance the value of turbulent diffusion, accelerating turbulent transport
Quantum and Classical Chaos in Kicked Coupled Jaynes-Cummings Cavities
We consider two Jaynes-Cummings cavities coupled periodically with a photon
hopping term. The semi-classical phase space is chaotic, with regions of
stability over some ranges of the parameters. The quantum case exhibits dynamic
localization and dynamic tunneling between classically forbidden regions. We
explore the correspondence between the classical and quantum phase space and
propose a scheme for implementing the system experimentally
Enhanced drag in pipe turbulent flow by an aqueous electrolyte: an electroviscous effect
Drag enhancement is reported for turbulent pipe flow of aqueous electrolyte solutions. No electroviscous effect was obtained with laminar flow. Nor was any unusual pressure drop observed for laminar or turbulent flow of non-electrolyte aqueous solutions such as sugar. An electroviscous theory was advanced that predicted the drag enhancement for a 1/1 electrolyte solution. The theory depended on consideration of Debye length
In praise of the referee
There has been a lively debate in many fields, including statistics and
related applied fields such as psychology and biomedical research, on possible
reforms of the scholarly publishing system. Currently, referees contribute so
much to improve scientific papers, both directly through constructive criticism
and indirectly through the threat of rejection. We discuss ways in which new
approaches to journal publication could continue to make use of the valuable
efforts of peer reviewers.Comment: 13 page
Structure of vortices in rotating Bose-Einstein condensates
We calculate the structure of individual vortices in rotating Bose-Einstein
condensates in a transverse harmonic trap. Making a Wigner-Seitz approximation
for the unit cell of the vortex lattice, we derive the Gross-Pitaevskii
equation for the condensate wave function in each cell of the lattice,
including effects of varying coarse grained density. We calculate the Abrikosov
parameter, the fractional core area, and the energy of individual cells.Comment: 10 pages, 9 figures, published versio
Mixed quartic-harmonic oscillators: A study of the ring puckering vibration of a cyclic amino acid dimer
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