scholarly journals Accumulation of a light non-aqueous phase liquid on a flat barrier baffling a descending groundwater flow

2012 ◽  
Vol 468 (2147) ◽  
pp. 3667-3684 ◽  
Author(s):  
A. R. Kacimov ◽  
Yu. V. Obnosov
Keyword(s):  
Two Dimensional ◽  
Heavy Fluid ◽  
Cross Sectional ◽  
Free Surfaces ◽  
New Class ◽  
Impermeable Barrier ◽  
Two Dimensional Flow ◽  
Phase Liquid ◽  
The Given ◽  
Vertical Height

The pioneering solution of Zhukovskii for a steady two-dimensional flow of an ideal heavy fluid with a nonlinear free boundary condition is extended to a Darcian flow of groundwater encumbered by an impermeable barrier. The stoss or/and lee sides of the barrier are covered by a macrovolume of a liquid contaminant. Explicit parametric equations of the sharp interface are obtained by inversion of the hodograph domain. Zhukovskii's gas-finger shape is shown to be a particular case of our new class of free surfaces. For a cap of a light liquid, partially covering the roof, from the given cross-sectional area of the cap, the affixes of the conformal mapping are found as a solution of a system of two nonlinear equations. The horizontal width and vertical height of the cap are determined. If the dimensionless incident velocity is higher than the density contrast, then the interface (cap boundary) cusps at its apex. For a relatively small velocity, the interface spreads to the vertices of the barrier, the apex zone remaining blunt shaped. We depict all the relevant domains and plot the flow nets using computer algebra routines.

Re-study on tensegrity footbridges based on ring modules

2019 ◽  
Vol 23 (5) ◽  
pp. 898-910
Author(s):  
Shun Gao ◽  
Xian Xu ◽  
Yaozhi Luo
Keyword(s):  
Parametric Study ◽  
Efficiency Index ◽  
Internal Space ◽  
Comprehensive Understanding ◽  
New Classification ◽  
Cross Sectional ◽  
Space Requirement ◽  
Structural Efficiency ◽  
New Class ◽  
The Given

A new class of tensegrity footbridges based on ring modules has been proposed and studied in the recent years. This article restudies the tensegrity footbridge and puts emphasis on some issues that are questionable or need further clarification in the previous studies. New cross-sectional sizes that satisfy the given internal space requirement are used for the tensegrity ring modules. The integral feasible prestresses of the tensegrity ring modules are determined and a new classification on the groups of members is proposed. A parametric study on the effects of cross-sectional areas of members and the level of prestress on the behavior of the tensegrity footbridge is carried out. The dominated parameters on the behavior of the tensegrity footbridge are identified. An improved structural efficiency index is proposed to evaluate the efficiency of the tensegrity footbridge. The effect of the number of modules on the structural efficiency index of the system is investigated. The reliability of the new index is verified through a comparison with the index proposed by a previous study. This article provides a more comprehensive understanding on the tensegrity footbridges based on ring modules.

scholarly journals A Two Dimensional Flow Analysis Model for Designing a Nozzle-Less Volute Casing for Radial Flow Gas Turbines

1991 ◽  
Author(s):  
H. O. Owarish ◽  
M. Ilyas ◽  
F. S. Bhinder
Keyword(s):  
Gas Turbines ◽  
Control Volume ◽  
Flow Analysis ◽  
Two Dimensional ◽  
Analysis Model ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Single Entry ◽  
Two Dimensional Flow ◽  
Control Volumes

This paper describes a two dimensional model for flow analysis and design of a single entry nozzle-less volute casing for inward flow radial turbines. The model takes into account the cross-sectional shape of the casing by dividing it into a number of segments which are further sub divided into control volumes. Changes in flow properties are calculated by considering the changes in momenta of fluid in the tangential and the radial directions across each control volume. The model, has been computerized using Fortran 77 for the IBM AT or 100% compatible micro computers.

scholarly journals Cavity flow past a slender pointed hydrofoil

1961 ◽  
Vol 11 (2) ◽  
pp. 187-208 ◽  
Author(s):  
E. Cumberbatch ◽  
T. Y. Wu
Keyword(s):  
Angle Of Attack ◽  
Cross Flow ◽  
The Body ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Slender Body Theory ◽  
Flow Past ◽  
Two Dimensional Flow ◽  
Cavity Boundary ◽  
The Cross

A slender-body theory for the flow past a slender, pointed hydrofoil held at a small angle of attack to the flow, with a cavity on the upper surface, has been worked out. The approximate solution valid near the body is seen to be the sum of two components. The first consists of a distribution of two-dimensional sources located along the centroid line of the cavity to represent the variation of the cross-sectional area of the cavity. The second component represents the cross-flow perpendicular to the centroid line. It is found that over the cavity boundary which envelops a constant pressure region, the magnitude of the cross-flow velocity is not constant, but varies to a moderate extent. With this variation neglected only in the neighbourhood of the hydrofoil, the cross-flow is solved by adopting the Riabouchinsky model for the two-dimensional flow. The lift is then calculated by intergrating the pressure along the chord; the dependence of the lift on cavitation number and angle of attack is shown for a specific case of the triangular plan form.

Three-dimensionally perturbed vortex tubes in a rotating flow

1997 ◽  
Vol 341 ◽  
pp. 127-163 ◽  
Author(s):  
G. F. CARNEVALE ◽  
M. BRISCOLIN ◽  
R. C. KLOOSTERZIEL ◽  
G. K. VALLIS
Keyword(s):  
Rotation Axis ◽  
Initial Perturbation ◽  
Maximum Amplitude ◽  
Small Scale ◽  
Rossby Number ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Small Perturbations ◽  
Two Dimensional Flow ◽  
Vortex Tubes

Numerical experiments are used to study the evolution of perturbed vortex tubes in a rotating environment in order to better understand the process of two-dimensionalization of unsteady rotating flows. We specifically consider non-axisymmetric perturbations to columnar vortices aligned along the axis of rotation. The basic unperturbed vortex is chosen to have a Gaussian cross-sectional vorticity distribution. The experiments cover a parameter space in which both the strength of the initial perturbation and the Rossby number are varied. The Rossby number is defined here as the ratio of the maximum amplitude of vorticity in the Gaussian vorticity profile to twice the ambient rotation rate. For small perturbations and small Rossby numbers, both cyclones and anticyclones behave similarly, relaxing rapidly back toward two-dimensional columnar vortices. For large perturbations and small Rossby numbers, a rapid instability occurs for both cyclones and anticyclones in which antiparallel vorticity is created. The tubes break up and then re-form again into columnar vortices parallel to the rotation axis (i.e. into a quasi-two-dimensional flow) through nonlinear processes. For Rossby numbers greater than 1, even small perturbations result in the complete breakdown of the anticyclonic vortex through centrifugal instability, while cyclones remain stable. For a range of Rossby numbers greater than 1, after the breakdown of the anticyclone, a new weaker anticyclone forms, with a small-scale background vorticity of spectral shape given approximately by the −5/3 energy spectral law.

Propellant Grain with Maximum Combustion Efficiency of Metal

2016 ◽  
Vol 685 ◽  
pp. 325-329
Author(s):  
Leonid Minkov ◽  
Ernst R. Shrager ◽  
Elizaveta V. Pikushchak
Keyword(s):  
Flow Field ◽  
Burning Rate ◽  
Combustion Efficiency ◽  
Metal Particles ◽  
Phase Flow ◽  
Two Dimensional ◽  
Two Phase ◽  
Cross Sectional ◽  
Analytical Correlation ◽  
Two Dimensional Flow

This paper reports on the ways of allocating the metal particles in the propellant grain of tube cross-sectional type to provide maximum combustion efficiency of metal. Two-dimensional flow field and the burning rate law govern a transport of the burning metal particles. The analytical correlation for the optimum allocation of metal particles in the case-bounded propellant grain of tube cross-sectional type under the assumption of equilibrium two-phase flow is deduced.

A Two-Dimensional Flow Analysis Model for Designing a Nozzle-less Volute Casing for Radial Flow Gas Turbines

1992 ◽  
Vol 114 (2) ◽  
pp. 402-410 ◽  
Author(s):  
H. O. Owarish ◽  
M. Ilyas ◽  
F. S. Bhinder
Keyword(s):  
Gas Turbines ◽  
Control Volume ◽  
Flow Analysis ◽  
Two Dimensional ◽  
Analysis Model ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Single Entry ◽  
Two Dimensional Flow ◽  
Control Volumes

This paper describes a two-dimensional model for flow analysis and design of a single entry nozzle-less volute casing for inward flow radial turbines. The model takes into account the cross-sectional shape of the casing by dividing it into a number of segments, which are further subdivided into control volumes. Changes in flow properties are calculated by considering the changes in momenta of fluid in the tangential and radial directions across each control volume. The model has been computerized using Fortran 77 for the IBM AT or 100 percent compatible microcomputers.

Two-Dimensional Flow of Polymer Solutions Through Porous Media

1999 ◽  
Vol 2 (3) ◽  
pp. 251-262
Author(s):  
P. Gestoso ◽  
A. J. Muller ◽  
A. E. Saez
Keyword(s):  
Porous Media ◽  
Polymer Solutions ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Two Dimensional Flow
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