scholarly journals A Study of Glacier Flow for an Open-Pit Mine: An Exercise in Applied Glaciology

1974 ◽  
Vol 13 (69) ◽  
pp. 401-414 ◽  
Author(s):  
S. C. Colbeck
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Greenland Ice Sheet ◽  
Field Work ◽  
Open Pit Mine ◽  
Open Pit ◽  
Two Dimensional ◽  
Ice Flow ◽  
Two Dimensional Flow ◽  
Glacier Flow

As part of the feasibility study for the development of an open-pit mine at the edge of the Greenland ice sheet, a study is made of the ice flow toward the proposed pit. The flow is analyzed by considering the two-dimensional flow along seven cross-sections. The most favorable profile is determined for each cross-section and its flow calculated. The excavation necessary to expose the ore is 106 × 106m3of ice. 66 × 106m3of ice will have to be removed in order to establish favorable profiles and an additional 7.9 × 106m3of ice will have to be removed each year in order to prevent the glacier from thickening and advancing into the mine. Many other glaciological problems must be considered, and field work continues in order to provide more information about the area.

scholarly journals A Study of Glacier Flow for an Open-Pit Mine: An Exercise in Applied Glaciology

1974 ◽  
Vol 13 (69) ◽  
pp. 401-414 ◽  
Author(s):  
S. C. Colbeck
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Greenland Ice Sheet ◽  
Field Work ◽  
Open Pit Mine ◽  
Open Pit ◽  
Two Dimensional ◽  
Ice Flow ◽  
Two Dimensional Flow ◽  
Glacier Flow

As part of the feasibility study for the development of an open-pit mine at the edge of the Greenland ice sheet, a study is made of the ice flow toward the proposed pit. The flow is analyzed by considering the two-dimensional flow along seven cross-sections. The most favorable profile is determined for each cross-section and its flow calculated. The excavation necessary to expose the ore is 106 × 106 m3 of ice. 66 × 106 m3 of ice will have to be removed in order to establish favorable profiles and an additional 7.9 × 106 m3 of ice will have to be removed each year in order to prevent the glacier from thickening and advancing into the mine. Many other glaciological problems must be considered, and field work continues in order to provide more information about the area.

The Two-Dimensional Aerodynamic Analysis of Various Cross-Sections of a Morphologically Accurate Bee Wing in Forward Flight

2017 ◽  
Author(s):  
Jeffrey Feaster ◽  
Francine Battaglia ◽  
Javid Bayandor
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Degrees Of Freedom ◽  
Radial Distance ◽  
Subject Area ◽  
Two Dimensional ◽  
Forward Flight ◽  
Wing Model ◽  
Μct Scan ◽  
Two Dimensional Flow

Bees sustain flight at extremely low Reynolds Numbers (500<Re<10,000) using three degrees of freedom and a flap frequency between 100 and 200 Hz. These combined mechanics create a complex vortex field that results in extraordinary agility and flight efficiency. In addition to agility and efficiency, bees are able to carry loads up to 80% of their body weight for miles making bee flight a very interesting subject area for drone and UAV related development. In order to better understand these complex fluid dynamics, Fluent is utilized to resolve the flow fields during forward flight for 4 anatomically accurate cross-sections of the bee wing at a speed of 1 m/s in two-dimensional flow. Each of the four cross-sections are taken at regular 1/6th wingspan intervals from the anatomically accurate bee wing model. The bee wing model was generated from a μCT scan of Bombus pensylvanicus with generalized bee kinematics presented in the literature. The kinematics applied to each cross-section are adjusted for the change in radial distance from the wing base. The presented analysis and discussion investigates the effects of the variation in cross-section and kinematics over the wing on vortex-shedding dynamics, and instantaneous aerodynamic forces.

Flow Visualization by Means of Contactless Inductive Flow Tomography in the Presence of a Magnetic Brake

2015 ◽  
Vol 15 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Matthias Ratajczak ◽  
Thomas Wondrak ◽  
Klaus Timmel ◽  
Frank Stefani ◽  
Sven Eckert
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Flow Field ◽  
Continuous Casting ◽  
Flow Structure ◽  
Cross Section ◽  
Two Dimensional ◽  
Slab Casting ◽  
Two Dimensional Flow

AbstractIn continuous casting DC magnetic fields perpendicular to the wide faces of the mold are used to control the flow in the mold. Especially in this case, even a rough knowledge of the flow structure in the mold would be highly desirable. The contactless inductive flow tomography (CIFT) allows to reconstruct the dominating two-dimensional flow structure in a slab casting mold by applying one external magnetic field and by measuring the flow-induced magnetic fields outside the mold. For a physical model of a mold with a cross section of 140 mm×35 mm we present preliminary measurements of the flow field in the mold in the presence of a magnetic brake. In addition, we show first reconstructions of the flow field in a mold with the cross section of 400 mm×100 mm demonstrating the upward scalability of CIFT.

scholarly journals Glacier disequilibrium in the Convoy Range, Transantarctic Mountains, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 269-276 ◽  
Author(s):  
T.J. Chinn
Keyword(s):  
Field Work ◽  
Snow Accumulation ◽  
Low Velocity ◽  
Ice Flow ◽  
Outlet Glacier ◽  
Regime Changes ◽  
Positive Balance ◽  
Geological Map ◽  
Glacier Flow ◽  
Surficial Deposits

Field work for a geological map of the Convoy Range included mapping glaciers, moraines and surficial deposits. A range of glaciological indicators, including supraglacial and other moraines and margin morphology, has been used to assess the present equilibrium of the glaciers. Fields of rafted supraglacial moraine have accumulated over long periods of time at specific low-gradient, low-velocity locations. As the glacier regime changes, the shape of the moraine field distorts, signalling a change in flow pattern. By reversing the ice flow vectors directed at the moraine field, the directions from whence the debris came are shown. Unsorting the contortions of supraglacial moraine fields reveals the nature of the changes in glacier regime. Moraine-field configurations all suggest that local glaciers are expanding in response to higher local precipitation, estimated to have occurred between 2000 and 8000 year BP, most likely coincident with the world-wide “climatic optimum” of about 6000 year BP.Ice-cliff morphology, fresh terminal moraines and boulder trains indicate that larger local glaciers are currently receding from a Holocene maximum, while the margin of the large Mackay Ice Sheet outlet glacier shows no evidence of recent recession and is probably close to its Holocene maximum. In contrast, areas of present snow cover are expanding, superimposing a recent positive balance (decades to hundreds of years), which has yet to reverse a general recession of mid- to high-altitude glaciers. Local hollows in some névé areas imply that glacier flow is not in equilibrium with snow accumulation.

scholarly journals Membrane analogy for multi-material bars under torsion

2019 ◽  
Vol 475 (2225) ◽  
pp. 20190124 ◽  
Author(s):  
Laura Galuppi ◽  
Gianni Royer-Carfagni
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Problem ◽  
Two Dimensional ◽  
Torsion Problem ◽  
Linear Elastic ◽  
Physical Apparatus

Prandtl's membrane analogy for the torsion problem of prismatic homogeneous bars is extended to multi-material cross sections. The linear elastic problem is governed by the same equations describing the deformation of an inflated membrane, differently tensioned in regions that correspond to the domains hosting different materials in the bar cross section, in a way proportional to the inverse of the material shear modulus. Multi-connected cross sections correspond to materials with vanishing stiffness inside the holes, implying infinite tension in the corresponding portions of the membrane. To define the interface constrains that allow to apply such a state of prestress to the membrane, a physical apparatus is proposed, which can be numerically modelled with a two-dimensional mesh implementable in commercial finite-element model codes. This approach presents noteworthy advantages with respect to the three-dimensional modelling of the twisted bar.

Towed Underwater SPIV Measurement of Flow Fields Around a Surface-Piercing Cylinder With Free Surface Effects

2015 ◽  
Author(s):  
Jeonghwa Seo ◽  
Bumwoo Han ◽  
Shin Hyung Rhee
Keyword(s):  
Boundary Layer ◽  
Free Surface ◽  
Surface Wave ◽  
Flow Field ◽  
Cross Section ◽  
Surface Effects ◽  
Flow Fields ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
Wave Induced

Effects of free surface on development of turbulent boundary layer and wake fields were investigated. By measuring flow field around a surface piercing cylinder in various advance speed conditions in a towing tank, free surface effects were identified. A towed underwater Stereoscopic Particle Image Velocimetry (SPIV) system was used to measure the flow field under free surface. The cross section of the test model was water plane shape of the Wigley hull, of which longitudinal length and width were 1.0 m and 100 mm, respectively. With sharp bow shape and slender cross section, flow separation was not expected in two-dimensional flow. Flow fields near the free-surface and in deep location that two-dimensional flow field was expected were measured and compared to identify free-surface effects. Some planes perpendicular to longitudinal direction near the model surface and behind the model were selected to track development of turbulent boundary layer. Froude numbers of the test conditions were from 0.126 to 0.40 and corresponding Reynolds numbers were from 395,000 to 1,250,000. In the lowest Froude number condition, free-surface wave was hardly observed and only free surface effects without surface wave could be identified while violent free-surface behavior due to wave-induced separation dominated the flow fields in the highest Froude number condition. From the instantaneous velocity fields, Time-mean velocity, turbulence kinetic energy, and flow structure derived by proper orthogonal decomposition (POD) were analyzed. As the free-surface effect, development of retarded wake, free-surface waves, and wave-induced separation were mainly observed.

scholarly journals Computational Study of Zigzag Spacer Design with Elliptical Cross-Section Filaments

2020 ◽  
Vol 307 ◽  
pp. 01047
Author(s):  
Gohar Shoukat ◽  
Farhan Ellahi ◽  
Muhammad Sajid ◽  
Emad Uddin
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Computational Study ◽  
Flow Direction ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Two Dimensional ◽  
Permeate Flux ◽  
Elliptical Cross

The large energy consumption of membrane desalination process has encouraged researchers to explore different spacer designs using Computational Fluid Dynamics (CFD) for maximizing permeate per unit of energy consumed. In previous studies of zigzag spacer designs, the filaments are modeled as circular cross sections in a two-dimensional geometry under the assumption that the flow is oriented normal to the filaments. In this work, we consider the 45° orientation of the flow towards the three-dimensional zigzag spacer unit, which projects the circular cross section of the filament as elliptical in a simplified two-dimensional domain. OpenFOAM was used to simulate the mass transfer enhancement in a reverse-osmosis desalination unit employing spiral wound membranes lined with zigzag spacer filaments. Properties that impact the concentration polarization and hence permeate flux were analyzed in the domain with elliptical filaments as well as a domain with circular filaments to draw suitable comparisons. The range of variation in characteristic parameters across the domain between the two different configurations is determined. It was concluded that ignoring the elliptical projection of circular filaments to the flow direction, can introduce significant margin of error in the estimation of mass transfer coefficient.

Studies on Design Optimization of Coronary Stents

2008 ◽  
Vol 2 (1) ◽  
Author(s):  
K. Srinivas ◽  
T. Nakayama ◽  
M. Ohta ◽  
S. Obayashi ◽  
T. Yamaguchi
Keyword(s):  
Design Optimization ◽  
Cross Sections ◽  
Latin Hypercube Sampling ◽  
Coronary Stents ◽  
Point Of View ◽  
Two Dimensional ◽  
Reattachment Length ◽  
Design Variables ◽  
Two Dimensional Flow ◽  
The Relationship

The stent design itself seems to be one of the factors responsible for restenosis. As a remedy, the present work attempts to perform a design optimization of coronary stents from a hemodynamic point of view. For the purpose, we have applied the principles of modern exploration of design space restricting ourselves to two-dimensional considerations. Width, thickness, and spacing of the struts of the stent formed the design variables. The objectives chosen for optimization were the vorticity generated, length of recirculation zone, and the reattachment distance in between the struts. Both semicircular and rectangular cross sections of stents were included. Starting with the range of design variables, sample stent cases were generated using Latin hypercube sampling. Objective functions were calculated for each of these by computing the two-dimensional flow using software FLUENT under the assumption of a steady, Newtonian flow considering a model stent with three struts. This was followed by Kriging to construct a response surface, which gives the relationship between the objectives and the design variables. The procedure gave nondominated fronts, which consist of optimized designs. Stents with minimum vorticity, with minimum recirculation distance, and the ones with maximum reattachment length in between struts were generated. The procedure is capable of producing the optimum set of design variables to achieve the prescribed objectives.

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