Experimental and numerical investigation of a forced circular shear layer

1988 ◽  
Vol 187 ◽  
pp. 115-140 ◽  
Author(s):  
J. M. Chomaz ◽  
M. Rabaud ◽  
C. Basdevant ◽  
Y. Couder
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
Shear Flow ◽  
Shear Layer ◽  
Flow Instability ◽  
Dynamical Behaviour ◽  
Small Cells ◽  
Stationary States ◽  
Two Dimensional ◽  
Shear Flow Instability

In a previous article we introduced a dissipative circular geometry in which stationary states of the shear flow instability were obtained. We show here that the dynamical behaviour of this flow depends strongly on the aspect ratio of the cell. In large cells, where the number of vortices is large, transitions from a mode with m vortices to a mode with (m−1) vortices occur through localized processes. In contrast to that situation, in small cells, transition takes place after a series of bifurcations which correspond to the successive breaking of all the symmetries of the flow.We show that, provided an adequate forcing term is introduced, a two-dimensional numerical simulation of this flow is sufficient to recover all the dynamical processes which characterize the experimental flow.

Shear-flow instability in a rotating fluid

1999 ◽  
Vol 387 ◽  
pp. 177-204 ◽  
Author(s):  
J. A. VAN DE KONIJNENBERG ◽  
A. H. NIELSEN ◽  
J. JUUL RASMUSSEN ◽  
B. STENUM
Keyword(s):  
Shear Flow ◽  
Shear Layer ◽  
Flow Instability ◽  
Experimental Situation ◽  
Point Vortex ◽  
Azimuthal Velocity ◽  
Rotating Fluid ◽  
Beta Effect ◽  
Vortex Chain ◽  
Shear Flow Instability

The instability of a forced, circular shear layer in a rotating fluid has been studied experimentally and numerically. The experiments were performed with a shallow layer of water in a parabolic tank, in which it is possible to apply radial pumping and to model a geophysical beta-effect. A shear layer was produced by a secondary rotation of the central part of the parabolic vessel. In most experiments, the shear layer takes on the appearance of a sequence of vortices, the number of which decreases with increasing strength of the shear. A beta-effect may prevent the formation of a steady vortex chain. Continuous pumping of fluid from the periphery to the centre or vice versa leads to an azimuthal velocity field corresponding to a point vortex. This azimuthal flow appears to stabilize the shear flow if it is opposite to the inner rotation, and to be destabilizing otherwise.The numerical investigations consist of the solution of the quasi-geostrophic equation in a geometry similar to the experimental situation and with a term modelling the experimental forcing. Though the numerical computations are based on a two-dimensional model, they capture the essential features of the instability and the resulting vortex structures.

scholarly journals The impact of magnetic fields on momentum transport and saturation of shear-flow instability by stable modes

2021 ◽  
Vol 28 (2) ◽  
pp. 022309
Author(s):  
A. E. Fraser ◽  
P. W. Terry ◽  
E. G. Zweibel ◽  
M. J. Pueschel ◽  
J. M. Schroeder
Keyword(s):  
Magnetic Fields ◽  
Shear Flow ◽  
Flow Instability ◽  
Momentum Transport ◽  
Shear Flow Instability ◽  
The Impact

A novel low inertia shear flow instability triggered by a chemical reaction

2007 ◽  
Vol 19 (8) ◽  
pp. 083102 ◽  
Author(s):  
Teodor Burghelea ◽  
Kerstin Wielage-Burchard ◽  
Ian Frigaard ◽  
D. Mark Martinez ◽  
James J. Feng
Keyword(s):  
Shear Flow ◽  
Chemical Reaction ◽  
Flow Instability ◽  
Shear Flow Instability

Numerical simulation of contaminant dispersion in estuary flows

1982 ◽  
Vol 381 (1780) ◽  
pp. 179-194 ◽  
Keyword(s):  
Numerical Simulation ◽  
Random Walk ◽  
Shear Flow ◽  
Diffusion Equation ◽  
New Method ◽  
Turbulent Shear ◽  
Two Dimensional ◽  
Turbulent Shear Flow ◽  
Oscillatory Flows ◽  
Contaminant Dispersion

The paper examines in detail the dispersion of a passive contaminant in steady and oscillatory turbulent shear flow in a two-dimensional channel. The aim of this examination is to understand dispersion in estuaries. A new method of analysing and predicting concentration distributions has been developed from work of Sullivan ( J. Fluid Mech . 49, 551–576 (1971)). A random walk technique is used, the contaminant being represented by a large number of marked particles whose paths are tracked as they move through the fluid. The technique seeks to model the physics of dispersion more realistically than the standard diffusion equation, and results from the simulation, with input based on data taken in the Mersey, show it to be a useful and versatile method of studying dispersion in oscillatory flows.

Shear flow instability in a conducting viscous fluid

1973 ◽  
Vol 57 (3) ◽  
pp. 481-490
Author(s):  
B. Roberts
Keyword(s):  
Magnetic Field ◽  
Shear Flow ◽  
Viscous Fluid ◽  
Flow Instability ◽  
Approximate Solutions ◽  
Viscous Fluids ◽  
Neutral Stability ◽  
Parallel Magnetic Field ◽  
The Stability ◽  
Shear Flow Instability

The effect of a parallel magnetic field upon the stability of the plane interface between two conducting viscous fluids in uniform relative motion is considered. A parameter reduction, which has not previously been noted, is employed to facilitate the solution of the problem. Neutral stability curves for unrestricted ranges of the governing parameters are found, and the approximate solutions of other authors are examined in this light.

Sign in / Sign up

Export Citation Format

Share Document