Note on the long wave stability of shear flows with variable bottom topography

2016 ◽  
Vol 10 ◽  
pp. 757-766
Author(s):  
K. Reena Priya ◽  
V. Ganesh
Keyword(s):  
Shear Flows ◽  
Bottom Topography ◽  
Wave Stability ◽  
Long Wave ◽  
Variable Bottom ◽  
Stability Of Shear Flows

scholarly journals Integral Constraints for Momentum and Energy in Zonal Flows with Parameterized Potential Vorticity Fluxes: Governing Parameters

2014 ◽  
Vol 44 (3) ◽  
pp. 922-943 ◽  
Author(s):  
V. O. Ivchenko ◽  
S. Danilov ◽  
B. Sinha ◽  
J. Schröter
Keyword(s):  
Ocean Circulation ◽  
Potential Vorticity ◽  
Channel Model ◽  
Bottom Topography ◽  
Flat Bottom ◽  
Zonal Flows ◽  
Integral Constraints ◽  
Variable Bottom ◽  
Eddy Fluxes ◽  
The Impact

Abstract Integral constraints for momentum and energy impose restrictions on parameterizations of eddy potential vorticity (PV) fluxes. The impact of these constraints is studied for a wind-forced quasigeostrophic two-layer zonal channel model with variable bottom topography. The presence of a small parameter, given by the ratio of Rossby radius to the width of the channel, makes it possible to find an analytical/asymptotic solution for the zonally and time-averaged flow, given diffusive parameterizations for the eddy PV fluxes. This solution, when substituted in the constraints, leads to nontrivial explicit restrictions on diffusivities. The system is characterized by four dimensionless governing parameters with a clear physical interpretation. The bottom form stress, the major term balancing the external force of wind stress, depends on the governing parameters and fundamentally modifies the restrictions compared to the flat bottom case. While the analytical solution bears an illustrative character, it helps to see certain nontrivial connections in the system that will be useful in the analysis of more complicated models of ocean circulation. A numerical solution supports the analytical study and confirms that the presence of topography strongly modifies the eddy fluxes.

Dissipative effects on the resonant flow of a stratified fluid over topography

1988 ◽  
Vol 192 ◽  
pp. 287-312 ◽  
Author(s):  
N. F. Smyth
Keyword(s):  
Bottom Topography ◽  
Stratified Fluid ◽  
Flow Speed ◽  
Resonant Condition ◽  
Weakly Nonlinear ◽  
Dissipative Effects ◽  
Long Wave ◽  
Near Resonance ◽  
Wave Limit ◽  
Wave Modes

The effect of dissipation on the flow of a stratified fluid over topography is considered in the weakly nonlinear, long-wave limit for the case when the flow is near resonance, i.e. the basic flow speed is close to a linear long-wave speed for one of the long-wave modes. The two types of dissipation considered are the dissipation due to viscosity acting in boundary layers and/or interfaces and the dissipation due to viscosity acting in the fluid as a whole. The effect of changing bottom topography on the flow produced by a force moving at a resonant velocity is also considered. In this case, the resonant condition is that the force velocity is close to a linear long-wave velocity for one of the long-wave modes. It is found that in most cases, these extra effects result in the formation of a steady state, in contrast to the flow without these effects, which remains unsteady for all time. The flow resulting under the action of boundary-layer dissipation is compared with recent experimental results.

Long‐wave motions in turbulent shear flows

1994 ◽  
Vol 6 (10) ◽  
pp. 3454-3464 ◽  
Author(s):  
V. G. Priymak ◽  
T. Miyazaki
Keyword(s):  
Shear Flows ◽  
Turbulent Shear ◽  
Long Wave ◽  
Turbulent Shear Flows

scholarly journals PERIODIC FLOWS FROM TIDAL INLETS

1978 ◽  
Vol 1 (16) ◽  
pp. 78
Author(s):  
D.L. Wilkinson
Keyword(s):  
Bottom Topography ◽  
Vortex Pair ◽  
Periodic Flows ◽  
Variable Bottom ◽  
Dominant Feature ◽  
Coastal Inlet ◽  
Offshore Flow ◽  
Rotational Motions ◽  
Starting Jet ◽  
Coastal Inlets

A study was undertaken of the flow produced in the offshore region by tidal currents at the entrance of a coastal inlet. The gross features of the offshore flow structure were examined in an idealised two dimensional model in which a sinusoidally reversing flow was discharged from an open channel into a large stagnant basin. During each period of ebb flow, the discharge from the simulated inlet developed a structure very similar to that of a starting jet, and a vortex pair was observed to form and ultimately became the dominant feature of the flow. Although variable bottom topography and long shore currents will distort the flow pattern, the rotational motions observed in these experiments would be expected to persist. The study was restricted to coastal inlets in which the sectional area of the entrance channel is several orders of magnitude smaller the area of water surface inside the inlet.

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