Mean flow generation along a sloping region in a rotating homogeneous fluid

1996 ◽  
Vol 101 (C12) ◽  
pp. 28597-28614 ◽  
Author(s):  
Xiuzhang Zhang ◽  
Don L. Boyer ◽  
Nicolas Pérenne ◽  
Dominique P. Renouard
Keyword(s):  
Mean Flow ◽  
Homogeneous Fluid ◽  
Flow Generation

scholarly journals Streaming by leaky surface acoustic waves

2010 ◽  
Vol 467 (2130) ◽  
pp. 1779-1800 ◽  
Author(s):  
J. Vanneste ◽  
O. Bühler
Keyword(s):  
Surface Waves ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Stokes Drift ◽  
Mean Flow ◽  
Matched Asymptotics ◽  
Flow Generation ◽  
Solid Liquid Interface ◽  
Solid Liquid

Acoustic streaming, the generation of mean flow by dissipating acoustic waves, provides a promising method for flow pumping in microfluidic devices. In recent years, several groups have been experimenting with acoustic streaming induced by leaky surface waves: (Rayleigh) surface waves excited in a piezoelectric solid interact with a small volume of fluid where they generate acoustic waves and, as result of the viscous dissipation of these waves, a mean flow. We discuss the computation of the corresponding Lagrangian mean flow, which controls the trajectories of fluid particles and hence the mixing properties of the flows generated by this method. The problem is formulated using the averaged vorticity equation which extracts the dominant balance between wave dissipation and mean-flow dissipation. Particular attention is paid to the thin boundary layer that forms at the solid/liquid interface, where the flow is best computed using matched asymptotics. This leads to an explicit expression for a slip velocity, which includes the effect of the oscillations of the boundary. The Lagrangian mean flow is naturally separated into three contributions: an interior-driven Eulerian mean flow, a boundary-driven Eulerian mean flow and the Stokes drift. A scale analysis indicates that the latter two contributions can be neglected in devices much larger than the acoustic wavelength but need to be taken into account in smaller devices. A simple two-dimensional model of mean flow generation by surface acoustic waves is discussed as an illustration.

Mean flow generation due to longitudinal librations of sidewalls of a rotating annulus

2020 ◽  
Vol 114 (6) ◽  
pp. 742-762
Author(s):  
Michael V. Kurgansky ◽  
Torsten Seelig ◽  
Marten Klein ◽  
Andreas Will ◽  
Uwe Harlander
Keyword(s):  
Mean Flow ◽  
Flow Generation

Mean flow generation in a two-layer system under circularly polarized vibrations

2011 ◽  
Vol 46 (4) ◽  
pp. 536-547
Author(s):  
D. V. Lyubimov ◽  
G. L. Khil’ko
Keyword(s):  
Mean Flow ◽  
Layer System ◽  
Circularly Polarized ◽  
Flow Generation

Hydraulic control of homogeneous shear flows

2003 ◽  
Vol 475 ◽  
pp. 163-172 ◽  
Author(s):  
CHRIS GARRETT ◽  
FRANK GERDES
Keyword(s):  
Shear Flow ◽  
Velocity Profile ◽  
Water Waves ◽  
Flow Speed ◽  
Hydraulic Control ◽  
Mean Flow ◽  
Shallow Water Waves ◽  
Homogeneous Fluid ◽  
Apparent Paradox ◽  
The Mean

If a shear flow of a homogeneous fluid preserves the shape of its velocity profile, a standard formula for the condition for hydraulic control suggests that this is achieved when the depth-averaged flow speed is less than (gh)1/2. On the other hand, shallow-water waves have a speed relative to the mean flow of more than (gh)1/2, suggesting that information could propagate upstream. This apparent paradox is resolved by showing that the internal stress required to maintain a constant velocity profile depends on flow derivatives along the channel, thus altering the wave speed without introducing damping. By contrast, an inviscid shear flow does not maintain the same profile shape, but it can be shown that long waves are stationary at a position of hydraulic control.

scholarly journals Rossby Waves and Jets in Two-Dimensional Decaying Turbulence on a Rotating Sphere

2007 ◽  
Vol 64 (12) ◽  
pp. 4246-4269 ◽  
Author(s):  
Yoshi-Yuki Hayashi ◽  
Seiya Nishizawa ◽  
Shin-ichi Takehiro ◽  
Michio Yamada ◽  
Keiichi Ishioka ◽  
...  
Keyword(s):  
Rossby Waves ◽  
Momentum Transport ◽  
Two Dimensional ◽  
Mean Flow ◽  
Jet Formation ◽  
Rotating Sphere ◽  
Angular Momentum Transport ◽  
Flow Generation ◽  
Flow Directions ◽  
Decaying Turbulence

Abstract Jet formation in decaying two-dimensional turbulence on a rotating sphere is reviewed from the viewpoint of Rossby waves. A series of calculations are performed to confirm the behavior of zonal mean flow generation on the parameter space of the rotation rate Ω and Froude number Fr. When the flow is nondivergent and Ω is large, intense easterly circumpolar jets tend to emerge in addition to the appearance of a banded structure of zonal mean flows with alternating flow directions. When the system allows surface elevation, circumpolar jets disappear and an equatorial easterly jet emerges with increasing Fr. The appearance of the intense easterly jets can be understood by the angular-momentum transport associated with the generation, propagation, and absorption of Rossby waves. When the flow is nondivergent, long Rossby waves tend to be absorbed near the poles. In contrast, when Fr is large, Rossby waves can hardly propagate poleward and tend to be absorbed near the equator.

scholarly journals Interference of lee waves over mountain ranges

2011 ◽  
Vol 11 (1) ◽  
pp. 27-32 ◽  
Author(s):  
N. I. Makarenko ◽  
J. L. Maltseva
Keyword(s):  
Ground Surface ◽  
Theoretical Models ◽  
Stationary Wave ◽  
Mountain Range ◽  
Mean Flow ◽  
Homogeneous Fluid ◽  
Mountain Ranges ◽  
Terrain Model ◽  
Lee Waves ◽  
Model Equations

Abstract. Internal waves in the atmosphere and ocean are generated frequently from the interaction of mean flow with bottom obstacles such as mountains and submarine ridges. Analysis of these environmental phenomena involves theoretical models of non-homogeneous fluid affected by the gravity. In this paper, a semi-analytical model of stratified flow over the mountain range is considered under the assumption of small amplitude of the topography. Attention is focused on stationary wave patterns forced above the rough terrain. Adapted to account for such terrain, model equations involves exact topographic condition settled on the uneven ground surface. Wave solutions corresponding to sinusoidal topography with a finite number of peaks are calculated and examined.

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