On the transient Leveque's problem with an application in electrochemistry

1981 ◽  
Vol 46 (13) ◽  
pp. 3209-3220 ◽  
Author(s):  
Ondřej Wein
Keyword(s):  
Mass Transfer ◽  
Shear Flow ◽  
Analytical Form ◽  
Step Change ◽  
Electrochemical Potential ◽  
Uniform Shear ◽  
Uniform Shear Flow ◽  
Efficient Data ◽  
Current Densities ◽  
Simple Analytical Form

The electrochemically induced unsteady mass transfer to a uniform shear flow from a local wall electrode subjected to a step change in electrochemical potential is studied. Due to neglecting the streamwise diffusion, the problem has two solutions which however differ only insignificantly. The resulting transient characteristics of current densities have a simple analytical form suitable for an efficient data treatment.

The heat/mass transfer to a finite strip at small Péclet numbers

1978 ◽  
Vol 86 (1) ◽  
pp. 49-65 ◽  
Author(s):  
R. C. Ackerberg ◽  
R. D. Patel ◽  
S. K. Gupta
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Shear Flow ◽  
Sodium Hydroxide Solution ◽  
Flow Direction ◽  
Mathematical Problem ◽  
Limiting Current ◽  
Transfer Rates ◽  
Uniform Shear ◽  
Uniform Shear Flow

The problem of heat transfer (or mass transfer at low transfer rates) to a strip of finite length in a uniform shear flow is considered. For small values of the Péclet number (based on wall shear rate and strip length), diffusion in the flow direction cannot be neglected as in the classical Leveque solution. The mathematical problem is solved by the method of matched asymptotic expansions and expressions for the local and overall dimensionless heat-transfer rate from the strip are found. Experimental data on wall mass-transfer rates in a tube at small Péclet numbers have been obtained by the well-known limiting-current method using potassium ferrocyanide and potassium ferricyanide in sodium hydroxide solution. The Schmidt number is large, so that a uniform shear flow can be assumed near the wall. Experimental results are compared with our theoretical predictions and the work of others, and the agreement is found to be excellent.

Development of the boundary layer at a free surface from a uniform shear flow

1966 ◽  
Vol 25 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Simon L. Goren
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Free Surface ◽  
Shear Flow ◽  
Surface Velocity ◽  
Cube Root ◽  
Two Dimensional ◽  
Uniform Shear ◽  
Uniform Shear Flow ◽  
Capillary Jets

The development of the boundary layer accompanying the formation of a free surface at y′ = 0, from the two-dimensional uniform shear flow u′ = ωyω, is discussed. The analysis shows that the surface velocity and surface position vary as the cube root of the distance downstream, while the mass-transfer coefficient varies inversely as the cube root of this distance. It is shown how these may be applied to the formation of capillary jets.

Formation of Vortex Street in Laminar Boundary Layer

1980 ◽  
Vol 47 (2) ◽  
pp. 227-233 ◽  
Author(s):  
M. Kiya ◽  
M. Arie
Keyword(s):  
Boundary Layer ◽  
Shear Flow ◽  
Laminar Boundary Layer ◽  
Solid Wall ◽  
Vortex Sheet ◽  
Vortex Street ◽  
Bluff Bodies ◽  
Uniform Shear ◽  
Uniform Shear Flow ◽  
Vortex Patterns

Main features of the formation of vortex street from free shear layers emanating from two-dimensional bluff bodies placed in uniform shear flow which is a model of a laminar boundary layer along a solid wall. This problem is concerned with the mechanism governing transition induced by small bluff bodies suspended in a laminar boundary layer. Calculations show that the background vorticity of shear flow promotes the rolling up of the vortex sheet of the same sign whereas it decelerates that of the vortex sheet of the opposite sign. The steady configuration of the conventional Karman vortex street is not possible in shear flow. Theoretical vortex patterns are experimentally examined by a flow-visualization technique.

The formation mechanism and shedding frequency of vortices from a sphere in uniform shear flow

1995 ◽  
Vol 287 ◽  
pp. 151-171 ◽  
Author(s):  
Hiroshi Sakamoto ◽  
Hiroyuki Haniu
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
Formation Mechanism ◽  
Vortex Shedding ◽  
Uniform Flow ◽  
Sphere Diameter ◽  
Uniform Shear ◽  
Uniform Shear Flow ◽  
Vortex Loops ◽  
Shear Parameter

Experiments to investigate the formation mechanism and frequency of vortex shedding from a sphere in uniform shear flow were conducted in a water channel using flow visualization and velocity measurement. The Reynolds number, defined in terms of the sphere diameter and approach velocity at its centre, ranged from 200 to 3000. The shear parameter K, defined as the transverse velocity gradient of the shear flow non-dimensionalized by the above two parameters, was varied from 0 to 0.25. The critical Reynolds number beyond which vortex shedding from the sphere occurred was found to be lower than that for uniform flow and decreased approximately linearly with increasing shear parameter. Also, the Strouhal number of the hairpin-shaped vortex loops became larger than that for uniform flow and increased as the shear parameter increased.The formation mechanism and the structure of vortex shedding were examined on the basis of series of photographs and subsequent image processing using computer graphics. The range of Reynolds number in the present investigation, extending up to 3000, could be classified into three regions on the basis of this study, and it was observed that the wake configuration did not differ substantially from that for uniform flow. Also, unlike the detachment point of vortex loops in uniform flow, which was irregularly located along the circumference of the sphere, the detachment point in shear flow was always on the high-velocity side.

scholarly journals Steady uniform shear flow in a low density granular gas

1997 ◽  
Vol 55 (3) ◽  
pp. 2846-2856 ◽  
Author(s):  
J. J. Brey ◽  
M. J. Ruiz-Montero ◽  
F. Moreno
Keyword(s):  
Shear Flow ◽  
Low Density ◽  
Uniform Shear ◽  
Uniform Shear Flow ◽  
Granular Gas

Application of the Large-Eddy Approach to the Simulation of Turbulence in Uniform Shear Flow

2005 ◽  
Vol 48 (6) ◽  
pp. 499-516 ◽  
Author(s):  
Yunliang Wang ◽  
Frank G. Jacobitz ◽  
Christopher J. Rutland
Keyword(s):  
Shear Flow ◽  
Uniform Shear ◽  
Uniform Shear Flow ◽  
Large Eddy
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