Dynamics of Electrodiffusion Friction Probes. I. Shape-Dependent Potentiostatic Transient

1997 ◽  
Vol 62 (3) ◽  
pp. 397-419 ◽  
Author(s):  
Ondřej Wein ◽  
Václav Sobolík
Keyword(s):  
Simple Formula ◽  
Flow Direction ◽  
Voltage Step ◽  
Convex Shape ◽  
Exact Theory ◽  
Working Electrode ◽  
Arbitrary Convex

An exact theory is given of the voltage-step transient under limiting diffusion conditions for an electrodiffusion friction probe of arbitrary convex shape. The actual transient courses are given for the strip, circular, elliptic, triangular, and rectangular probes of any orientation with respect to the flow direction. A simple formula for any probe with a single working electrode of convex shape is suggested to facilitate the calibration of electrodiffusion probes based on the voltage-step transient.

The Estimation of Laminar Skin Friction, including the Effects of Distributed Suction

1960 ◽  
Vol 11 (1) ◽  
pp. 1-21 ◽  
Author(s):  
N. Curle
Keyword(s):  
Boundary Layer ◽  
Skin Friction ◽  
Laminar Boundary Layer ◽  
Simple Formula ◽  
Outer Part ◽  
Order Correction ◽  
Viscous Effects ◽  
Viscous Forces ◽  
Exact Theory ◽  
Total Head

SummaryStratford's analysis of the laminar boundary layer near separation uses two physical ideas. In the outer part of the boundary layer, where viscous effects are small, the development is given by the condition that the total head is constant along streamlines, apart from a second-order correction for viscosity. Near the wall, however, viscous forces must balance the pressure forces, and the profile adjusts itself accordingly. Quantitatively these ideas yield a simple formula for predicting separation, which has been found to be particularly accurate.In this paper it is indicated how the same approach may be used to yield the full distribution of skin friction along the wall. Further, the effects of suction may be incorporated into the method. Physically, suction affects the outer part of the boundary layer in that the streamlines are drawn towards the wall when suction is applied. At the wall, the balance between viscous and pressure forces is influenced by the momentum of the fluid which is sucked away. When these effects are accounted for quantitatively, the resulting formula for the skin friction is still very simple.Several examples are considered, and comparison is made with exact theory and with approximate results by other methods. It is indicated that the method has a useful range of validity.

Grains3D, a flexible DEM approach for particles of arbitrary convex shape — Part I: Numerical model and validations

2012 ◽  
Vol 224 ◽  
pp. 374-389 ◽  
Author(s):  
Anthony Wachs ◽  
Laurence Girolami ◽  
Guillaume Vinay ◽  
Gilles Ferrer
Keyword(s):  
Numerical Model ◽  
Convex Shape ◽  
Arbitrary Convex

scholarly journals Drag of Bodies with Arbitrary Gas-surface Accommodation in a Free-molecule Flow

1973 ◽  
Vol 28 (9) ◽  
pp. 1468-1471 ◽  
Author(s):  
I. Kuščer ◽  
H. Lang
Keyword(s):  
Heat Flux ◽  
Gas Flow ◽  
Surface Interaction ◽  
Free Molecule ◽  
Uniform Temperature ◽  
Convex Shape ◽  
Accommodation Coefficients ◽  
Arbitrary Convex ◽  
Molecule Flow

A body of arbitrary convex shape and uniform temperature is thought to be placed in a freemolecule gas flow. In the near-equilibrium regime the four Knudsen accommodation coefficients suffice to express the drag and absorbed heat flux. Extensions to higher speeds require more information − or assumptions − on the gas-surface interaction, as is made clear by the case with Ma ≫ 1.

scholarly journals Grains3D, a flexible DEM approach for particles of arbitrary convex shape—Part III: extension to non-convex particles modelled as glued convex particles

2018 ◽  
Vol 6 (1) ◽  
pp. 55-84 ◽  
Author(s):  
Andriarimina Daniel Rakotonirina ◽  
Jean-Yves Delenne ◽  
Farhang Radjai ◽  
Anthony Wachs
Keyword(s):  
Convex Shape ◽  
Arbitrary Convex

Analytical solution for estimating the influence of a pre-existing ground water flow on a geothermal heat production-injection well system

2011 ◽  
Vol 2 (1) ◽  
pp. 13-17
Author(s):  
I. David ◽  
M. Visescu
Keyword(s):  
Ground Water ◽  
Water Flow ◽  
Geothermal Energy ◽  
Flow Direction ◽  
Energy Resource ◽  
Hot Water ◽  
Injection Well ◽  
Production Well ◽  
Ground Water Flow ◽  
The Earth

Abstract Geothermal energy source is the heat from the Earth, which ranges from the shallow ground (the upper 100 m of the Earth) to the hot water and hot rock which is a few thousand meters beneath the Earth's surface. In both cases the so-called open systems for geothermal energy resource exploitation consist of a groundwater production well to supply heat energy and an injection well to return the cooled water, from the heat pump after the thermal energy transfer, in the underground. In the paper an analytical method for a rapid estimation of the ground water flow direction effect on the coupled production well and injection well system will be proposed. The method will be illustrated with solutions and images for representative flow directions respect to the axis of the production/injection well system.

EFFECT OF GAS FLOW DIRECTION ON PASSIVE SUBSEA COOLER EFFECTIVENESS

2019 ◽  
Vol 11 (1-2) ◽  
pp. 1-16 ◽  
Author(s):  
Nikolay Ivanov ◽  
Vladimir V. Ris ◽  
Nikolay A. Tschur ◽  
Marina Zasimova
Keyword(s):  
Gas Flow ◽  
Flow Direction
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