A Note on Oscillatory Couette Flow in a Rotating System

1994 ◽  
Vol 61 (1) ◽  
pp. 208-209 ◽  
Author(s):  
R. Ganapathy
Keyword(s):  
Boundary Layer ◽  
Couette Flow ◽  
Relative Motion ◽  
Boundary Layer Flow ◽  
Alternative Solution ◽  
Parallel Plates ◽  
Rotating System ◽  
Rotating Systems ◽  
Ekman Boundary Layer ◽  
Layer Flow

An alternative solution is proposed for the oscillatory Ekman boundary layer flow bounded by two parallel plates in relative motion (Muzumder, 1991). The solution brings out among other things, the phenomenon of resonance which is of importance in rotating systems.

An Exact Solution of Oscillatory Couette Flow in a Rotating System

1991 ◽  
Vol 58 (4) ◽  
pp. 1104-1107 ◽  
Author(s):  
B. S. Mazumder
Keyword(s):  
Boundary Layer ◽  
Exact Solution ◽  
Unsteady Flow ◽  
Couette Flow ◽  
Coriolis Force ◽  
Boundary Layer Flow ◽  
Shear Stresses ◽  
Flat Plates ◽  
Rotating System ◽  
Layer Flow

An exact solution of oscillatory Ekman boundary layer flow bounded by two horizontal flat plates, one of which is oscillating in its own plane and other at rest, is obtained. The effect of coriolis force on the resultant velocities and shear stresses for steady and unsteady flow has been studied.

Axisymmetric and three-dimensional instabilities in an Ekman boundary layer flow

2001 ◽  
Vol 22 (1) ◽  
pp. 82-93 ◽  
Author(s):  
E. Serre ◽  
S. Hugues ◽  
E. Crespo del Arco ◽  
A. Randriamampianina ◽  
P. Bontoux
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Ekman Boundary Layer ◽  
Layer Flow

Stability of compressible Ekman boundary-layer flow

1984 ◽  
Vol 147 (-1) ◽  
pp. 159 ◽  
Author(s):  
Hans Moberg ◽  
Lennart S. Hultgren ◽  
Fritz H. Bark
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Ekman Boundary Layer ◽  
Layer Flow

An experimental study of the instability of the laminar Ekman boundary layer

1963 ◽  
Vol 15 (4) ◽  
pp. 560-576 ◽  
Author(s):  
Alan J. Faller
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Rotating Disk ◽  
Homogeneous Fluid ◽  
Viscous Boundary Layer ◽  
Ekman Boundary Layer ◽  
Characteristic Angle ◽  
Layer Flow ◽  
The Stability ◽  
Viscous Boundary

This study concerns the stability of the steady laminar boundary-layer flow of a homogeneous fluid which occurs in a rotating system when the relative flow is slow compared to the basic speed of rotation. Such a flow is called an Ekman boundary-layer flow after V. W. Ekman who considered the theory of such flows with application to the wind-induced drift of the surface waters of the ocean.Ekman flow was produced in a large cylindrical rotating tank by withdrawing water from the centre and introducing it at the rim. This created a steady-state symmetrical vortex in which the flow from the rim to the centre took place entirely in the shallow viscous boundary layer at the bottom. This boundary-layer flow became unstable above the critical Reynolds number$Re_c = vD|v = 125 \pm 5$wherevis the tangential speed of flow,$D = (v| \Omega)^{\frac {1}{2}}$is the characteristic depth of the boundary layer,vis the kinematic viscosity, and Ω is the basic speed of rotation. The initial instability was similar to that which occurs in the boundary layer on a rotating disk, having a banded form with a characteristic angle to the basic flow and with the band spacing proportional to the depth of the boundary layer.

A problem of a micropolar magnetohydrodynamic boundary-layer flow

2000 ◽  
Vol 77 (10) ◽  
pp. 813-827 ◽  
Author(s):  
M A Ezzat ◽  
M I Othman ◽  
K A Helmy
Keyword(s):  
Boundary Layer ◽  
Laplace Transform ◽  
Boundary Layer Flow ◽  
Plane Surface ◽  
Broad Class ◽  
Vertical Plane ◽  
Transverse Magnetic ◽  
Infinite Plane ◽  
Parallel Plates ◽  
Layer Flow

The matrix exponential method, which constitutes the basis of the state space approach of modern control theory, is applied to the nondimensional equations of unsteady boundary layer flow past an infinite plane surface with a pressure gradient. Laplace-transform techniques are used. The results obtained can be used to generate solutions in the Laplace-transform domain to a broad class of problems in magneto-hydrodynamic boundary layer flow. The technique is applied to the problem of an electrically conducting micropolar fluid flowing past a vertical plane surface in the presence of a transverse magnetic field and to the problem of flow between two parallel plates. A numerical method is employed for the inversion of the Laplace-transforms. Numerical results are given and illustrated graphically for both problems.PACS No.: 47.65+a

Bounds on the momentum transport by turbulent shear flow in rotating systems

2007 ◽  
Vol 583 ◽  
pp. 303-311 ◽  
Author(s):  
F. H. BUSSE
Keyword(s):  
Relative Motion ◽  
Vector Fields ◽  
Fluid Velocity ◽  
Momentum Transport ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Parallel Plates ◽  
Rotating System ◽  
Rotating Systems ◽  
Energy Balances

Bounds on the momentum transport by laminar or turbulent shear flows between two parallel plates in constant relative motion in a rotating system are derived. The axis of rotation is parallel to the plates. The dimensionless component of the rotation vector perpendicular to the relative motion of the plate is denoted by the Coriolis number τ. Through the consideration of separate energy balances for the poloidal and the toroidal components of the fluid velocity field a variational problem is formulated in which τ enters as a parameter. Bounds that are derived under the hypothesis that the extremalizing vector fields are independent of the streamwise coordinate suggest that no state of turbulent motion can exist for $-2\sqrt{1708} \equiv -\hbox{\it Re}_E \leq \hbox{\it Re} \leq 1708/\tau + \tau$ with $\tau \gtrsim \sqrt{1708}$.

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