Saline and particle-driven interfacial intrusions

1999 ◽  
Vol 389 ◽  
pp. 303-334 ◽  
Author(s):  
FRANS DE ROOIJ ◽  
P. F. LINDEN ◽  
STUART B. DALZIEL
Keyword(s):  
Experimental Investigation ◽  
Relative Density ◽  
Propagation Velocity ◽  
Laboratory Experiments ◽  
Interstitial Fluid ◽  
Gravity Currents ◽  
Integral Model ◽  
Sediment Distribution ◽  
Front Position ◽  
Good Agreement

This paper presents a theoretical and experimental investigation into saline and particle-driven intrusions along the interface between two layers of different densities. The conditions at the nose of an intrusion are described in an analysis similar to that applied by Benjamin (1968) to boundary gravity currents. Equations for propagation velocity and front position as functions of relative density are derived. These are used in an integral model for intrusions, which also includes the effects of sedimentation of particles and detrainment of interstitial fluid. The model describes the time-evolution of the length of the intrusion and the sediment distribution it produces. Laboratory experiments were carried out with lock-releases of a fixed volume of saline or particle-laden fluid into a two-layer stratification. Measurements were taken of the intrusion propagation, intrusion position and sediment distribution, and are found to be in good agreement with the solutions of the integral model.

On the application of box models to particle-driven gravity currents

2000 ◽  
Vol 416 ◽  
pp. 187-195 ◽  
Author(s):  
CHARLOTTE GLADSTONE ◽  
ANDREW W. WOODS
Keyword(s):  
Experimental Data ◽  
Froude Number ◽  
Laboratory Experiments ◽  
Interstitial Fluid ◽  
Gravity Currents ◽  
Box Model ◽  
Monodisperse Particle ◽  
Box Models ◽  
Exchange Particle ◽  
Different Types

New laboratory experiments on different types of lock-exchange particle-driven gravity currents advancing into a flume of fresh water are presented. These include purely saline currents, monodisperse particle-laden gravity currents with both fresh and saline interstitial fluid, and bidisperse particle-laden currents. For each case a simple box model is developed. These agree well with the experimental data. We find that particulate gravity currents with saline interstitial fluid flowing into ambient fresh fluid are best described using a Froude number of 0.52 in the box model (cf. Huppert & Simpson 1980). However, particulate gravity currents with fresh interstitial fluid are best described using a higher Froude number of 0.67. The change in Froude number reflects the different shape and structure associated with the different density of interstitial fluid. For all experiments, box models provide accurate predictions for up to twenty lock-lengths.

scholarly journals Dynamics of viscous grounding lines

2010 ◽  
Vol 648 ◽  
pp. 363-380 ◽  
Author(s):  
ROSALYN A. V. ROBISON ◽  
HERBERT E. HUPPERT ◽  
M. GRAE WORSTER
Keyword(s):  
Laboratory Experiments ◽  
Gravity Current ◽  
Ice Sheets ◽  
Gravity Currents ◽  
Solid Base ◽  
Leading Order ◽  
Ice Shelves ◽  
Grounding Line ◽  
Theoretical Predictions ◽  
Good Agreement

We have used viscous fluids in simple laboratory experiments to explore the dynamics of grounding lines between marine ice sheets and the freely floating ice shelves into which they develop. We model the ice sheets as shear-dominated gravity currents, and the ice shelves as extensional gravity currents having zero shear to leading order. We consider the flow of viscous fluid down an inclined plane into a dense inviscid ‘ocean’. A fixed flux of fluid is supplied at the top of the plane, which is at ‘sea level’. The fluid forms a gravity current flowing down and attached to the plane for some distance before detaching to form a freely floating extensional current. We have derived a mathematical model of the flow that incorporates a new dynamic boundary condition for the position of the grounding line, where the gravity current loses contact with the solid base. The grounding line initially advances and eventually reaches a steady position. Good agreement between our theoretical predictions and experimental measurements and observations gives confidence in the fundamental assumptions of our model.

A study of three-dimensional gravity currents on a uniform slope

2002 ◽  
Vol 453 ◽  
pp. 239-261 ◽  
Author(s):  
ANDREW N. ROSS ◽  
P. F. LINDEN ◽  
STUART B. DALZIEL
Keyword(s):  
Laboratory Experiments ◽  
Gravity Current ◽  
Three Dimensional ◽  
Gravity Currents ◽  
Integral Model ◽  
Conductivity Measurements ◽  
Dense Fluid ◽  
Wedge Shape ◽  
Dimensional Gravity ◽  
Shallow Water Models

In many geophysical, environmental and industrial situations, a finite volume of fluid with a density different to the ambient is released on a sloping boundary. This leads to the formation of a gravity current travelling up, down and across the slope. We present novel laboratory experiments in which the dense fluid spreads both down-slope (and initially up-slope) and laterally across the slope. The position, shape and dilution of the current are determined through video and conductivity measurements for moderate slopes (5° to 20°). The entrainment coefficient for different slopes is calculated from the experimental results and is found to depend very little on the slope. The value agrees well with previously published values for entrainment into gravity currents on a horizontal surface. The experimental measurements are compared with previous shallow-water models and with a new wedge integral model developed and presented here. It is concluded that these simplified models do not capture all the significant features of the flow. In the models, the current takes the form of a wedge which travels down the slope, but the experiments show the formation of a more complicated current. It is found that the wedge integral model over-predicts the length and width of the gravity current but gives fair agreement with the measured densities in the head. The initial stages of the flow, during which time the wedge shape develops, are studied. It is found that although the influence of the slope is seen relatively quickly for moderate slopes, the time taken for the wedge to develop is much longer. The implications of these findings for safety analysis are briefly discussed.

Experimental investigation and modelling of light scattering in a-Si:H solar cells deposited on glass/ZnO:Al substrates

2002 ◽  
Vol 715 ◽  
Author(s):  
J. Krc ◽  
M. Zeman ◽  
O. Kluth ◽  
F. Smole ◽  
M. Topic
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Solar Cells ◽  
Angular Distribution ◽  
Light Scattering ◽  
Optical Model ◽  
Distribution Functions ◽  
Interface Roughness ◽  
Scattering Parameters ◽  
Good Agreement

AbstractThe descriptive scattering parameters, haze and angular distribution functions of textured ZnO:Al transparent conductive oxides with different surface roughness are measured. An approach to determine the scattering parameters of all internal interfaces in p-i-n a-Si:H solar cells deposited on the glass/ZnO:Al substrates is presented. Using the determined scattering parameters as the input parameters of the optical model, a good agreement between the measured and simulated quantum efficiencies of the p-i-n a-Si:H solar cells with different interface roughness is achieved.

Experimental Investigation on the Effect of Arm Length on Accuracy of Torque Wrench

2016 ◽  
Vol 853 ◽  
pp. 216-220 ◽  
Author(s):  
You Gang Peng ◽  
Yong Wang
Keyword(s):  
Experimental Investigation ◽  
Structural Design ◽  
Bending Moment ◽  
Theoretical Solution ◽  
Calibration Laboratory ◽  
Moment Measurement ◽  
Torque Wrench ◽  
Actual Use ◽  
Good Agreement

Experiments were carried out to investigate the effect of arm length on the accuracy of two typical conventional torque wrenches, namely, setting type torque wrench (STW) and indicating type torque wrench (ITW). The experiment results demonstrate that the measurement values of STW rises rapidly with decreasing arm length while measured torque of ITW shows irrelevant to arm length. Theoretical solution with respect to STW shows quite good agreement with experiment results. Irrelevance of arm length regard to ITW may be attributable to compensation of bending moment measurement due to proper arrangement of circuit and structural design. In order to conduct a proper assessment at a calibration laboratory or ensure its reliability with reference to actual use conditions, a torque wrench should be used by a customer at the loading point as recommended.

Laboratory experiments and shallow water simulations of gravity currents moving on flat and up-sloping beds

2014 ◽  
pp. 89-95
Author(s):  
C Adduce ◽  
V Lombardi ◽  
G Sciortino ◽  
M La Rocca ◽  
M Morganti
Keyword(s):  
Shallow Water ◽  
Laboratory Experiments ◽  
Gravity Currents

Experimental Investigation on the Influence of Relative Density on the Compressive Behaviour of Metal Mesh Isolator

2017 ◽  
pp. 941-947 ◽  
Author(s):  
Fares Mezghani ◽  
Alfonso Fernandez Del Rincon ◽  
Mohamed Amine Ben Souf ◽  
Pablo Garcia Fernandez ◽  
Fakher Chaari ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Relative Density ◽  
Metal Mesh ◽  
Compressive Behaviour

Theoretical and Experimental Investigation on Forming Limit for TNW700 Titanium Alloy

2014 ◽  
Vol 622-623 ◽  
pp. 340-346 ◽  
Author(s):  
Bao Sheng Liu ◽  
Wei Wu ◽  
Xiu Quan Han
Keyword(s):  
Experimental Investigation ◽  
Titanium Alloy ◽  
High Temperature ◽  
Forming Limit ◽  
Minor Strain ◽  
Resistant Material ◽  
Dimple Rupture ◽  
Short Time ◽  
Fractographic Observation ◽  
Good Agreement

Forming limit is identified to evaluate the formability of sheet metal. The in-plane limit strains of sheets are plotted in a diagram with coordinates of major strain vs. minor strain. TNW700 titanium alloy is a high temperature resistant material. The products made of TNW700 can be used in a long serving period at 500°C, short time at 700°C. In this work, the forming limit of TNW700 will be investigated in theoretical and experimental ways. The experiment to test limit strains was carried out at 750°C under different loading paths. Marciniak – Kuczynski (M-K) model was calculated with Swift constitutive equations to predict the curves of limit strains. The effect of the groove angle on forming limit is that, the same angle on both sides of centerline determines the same FLC, and the limit points shift from left side to right side. The experiment shows that, the formability of TNW700 is not excellent, and it is lower than that of TC4 and TA15 at the same condition. The comparison shows that the curve predicted by M-K model is in a good agreement with that at plane strain, however higher than that in both sides. The fractographic observation shows that the fracture mode of TNW700 is dimple rupture.

scholarly journals Axisymmetric viscous gravity currents flowing over a porous medium

2009 ◽  
Vol 622 ◽  
pp. 135-144 ◽  
Author(s):  
MELISSA J. SPANNUTH ◽  
JEROME A. NEUFELD ◽  
J. S. WETTLAUFER ◽  
M. GRAE WORSTER
Keyword(s):  
Porous Medium ◽  
Steady State ◽  
Gravity Current ◽  
Gravity Currents ◽  
Constant Input ◽  
Radial Extent ◽  
Vertically Aligned ◽  
Analytical Expressions ◽  
Permeability Structure ◽  
Good Agreement

We study the axisymmetric propagation of a viscous gravity current over a deep porous medium into which it also drains. A model for the propagation and drainage of the current is developed and solved numerically in the case of constant input from a point source. In this case, a steady state is possible in which drainage balances the input, and we present analytical expressions for the resulting steady profile and radial extent. We demonstrate good agreement between our experiments, which use a bed of vertically aligned tubes as the porous medium, and the theoretically predicted evolution and steady state. However, analogous experiments using glass beads as the porous medium exhibit a variety of unexpected behaviours, including overshoot of the steady-state radius and subsequent retreat, thus highlighting the importance of the porous medium geometry and permeability structure in these systems.

Preliminary studies of the development of a clogging prediction method for stormwater infiltration systems

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
N.R. Siriwardene ◽  
A. Deletic ◽  
T.D. Fletcher
Keyword(s):  
Laboratory Experiments ◽  
Prediction Method ◽  
Sediment Distribution ◽  
Popular Approach ◽  
One Dimensional ◽  
Fine Sediments ◽  
High Incidence ◽  
Fundamental Understanding ◽  
Stormwater Infiltration ◽  
Underlying Soil

Infiltration systems have become a popular approach to managing stormwater. However, a high incidence of failure due to clogging has been found in these systems. A study has thus been undertaken to develop a fundamental understanding of the clogging processes, by conducting one dimensional (1D-Rig) and two dimensional (2D-Rig) laboratory experiments, and based on this knowledge, to develop a new method for clogging prediction. So far, constant and fluctuating stormwater level flow regimes in the systems have been studied. This paper presents the methods and compares the results of 1D and 2D rig constant water level experiments. It was found that a clogging layer was formed at the interface between the filter and underlying soil, irrespective of sediment distribution within the filter. It was also found that the very fine sediments were enough to clog the system.

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