Phenomenological Approach to Flow and Volume Change in Soils and Other Media

1995 ◽  
Vol 48 (10) ◽  
pp. 650-658 ◽  
Author(s):  
J. R. Philip

We review the phenomenological approach, on the macroscopic or Darcy scale, to flow and volume change in clays and other swelling media. The formulation represents the generalization to media subject to volume change of the well-established phenomenological approach to flow in non-swelling media primarily established in the context of soil physics. The one-dimensional generalization to swelling media is straightforward, and may be usefully applied to practical one-dimensional systems, including three-component systems with solid particles, water, and air. On the other hand, the further generalizations to two- and three-dimensional systems have not yet been developed fully convincingly. Difficult questions include the mode of stress transmission and the tensorial stress-strain relations in multidimensional and multi-component systems. One means of gaining insight into these questions for media of high colloid content (such as clays) is through relevant solutions of the Poisson-Boltzmann equation governing electrical double-layer interactions in dense arrays of colloidal particles. These solutions give pertinent information on both the macroscopic and the microscopic scales. We present a progress report on work along these lines.

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.


2021 ◽  
Author(s):  
Daria Gladskikh ◽  
Evgeny Mortikov ◽  
Victor Stepanenko

<p>The study of thermodynamic and biochemical processes of inland water objects using one- and three-dimensional RANS numerical models was carried out both for idealized water bodies and using measurements data. The need to take into account seiche oscillations to correctly reproduce the deepening of the upper mixed layer in one-dimensional (vertical) models is demonstrated. We considered the one-dimensional LAKE model [1] and the three-dimensional model [2, 3, 4] developed at the Research Computing Center of Moscow State University on the basis of a hydrodynamic code combining DNS/LES/RANS approaches for calculating geophysical turbulent flows. The three-dimensional model was supplemented by the equations for calculating biochemical substances by analogy with the one-dimensional biochemistry equations used in the LAKE model. The effect of mixing processes on the distribution of concentration of greenhouse gases, in particular, methane and oxygen, was studied.</p><p>The work was supported by grants of the RF President’s Grant for Young Scientists (MK-1867.2020.5, MD-1850.2020.5) and by the RFBR (19-05-00249, 20-05-00776). </p><p>1. Stepanenko V., Mammarella I., Ojala A., Miettinen H., Lykosov V., Timo V. LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes // Geoscientific Model Development. 2016. V. 9(5). P. 1977–2006.<br>2. Mortikov E.V., Glazunov A.V., Lykosov V.N. Numerical study of plane Couette flow: turbulence statistics and the structure of pressure-strain correlations // Russian Journal of Numerical Analysis and Mathematical Modelling. 2019. 34(2). P. 119-132.<br>3. Mortikov, E.V. Numerical simulation of the motion of an ice keel in stratified flow // Izv. Atmos. Ocean. Phys. 2016. V. 52. P. 108-115.<br>4. Gladskikh D.S., Stepanenko V.M., Mortikov E.V. On the influence of the horizontal dimensions of inland waters on the thickness of the upper mixed layer // Water Resourses. 2021.V. 45, 9 pages. (in press) </p>


1981 ◽  
Vol 42 (19) ◽  
pp. 445-449 ◽  
Author(s):  
A. Fournel ◽  
C. More ◽  
G. Roger ◽  
J.P. Sorbier ◽  
J.M. Delrieu ◽  
...  

Author(s):  
D. Pulgarín ◽  
J. Plaza ◽  
J. Ruge ◽  
J. Rojas

This study proposes a methodology for the calibration of combined sewer overflow (CSO), incorporating the results of the three-dimensional ANSYS CFX model in the SWMM one-dimensional model. The procedure consists of constructing calibration curves in ANSYS CFX that relate the input flow to the CSO with the overflow, to then incorporate them into the SWMM model. The results obtained show that the behavior of the flow over the crest of the overflow weir varies in space and time. Therefore, the flow of entry to the CSO and the flow of excesses maintain a non-linear relationship, contrary to the results obtained in the one-dimensional model. However, the uncertainty associated with the idealization of flow methodologies in one dimension is reduced under the SWMM model with kinematic wave conditions and simulating CSO from curves obtained in ANSYS CFX. The result obtained facilitates the calibration of combined sewer networks for permanent or non-permanent flow conditions, by means of the construction of curves in a three-dimensional model, especially when the information collected in situ is limited.


1979 ◽  
Vol 101 (4) ◽  
pp. 225-231 ◽  
Author(s):  
E. S. Grood ◽  
C. A. Phillips ◽  
R. E. Mates

A three-dimensional composite model of heart muscle is proposed, consisting of one-dimensional (uniaxial) active contractile filaments embedded in a passive elastic binder. Equations are developed which relate the force developed by the filaments to the local tissue stress. An approximate analysis is employed to determine the time variation of the contractile filament stress throughout the cardiac cycle from catheterization data. Results from 15 patients with normal left ventricles demonstrate that the stress developed by the contractile filaments is up to 25 percent more tensile than the wall stress, and that the binder stress is compressive during most of systole. In contrast, the one-dimensional lumped parameter muscle models previously employed predict active (CE) stresses less tensile than the wall stress and binder (PE) stresses that are tensile. We conclude that the use of a one-dimensional muscle model results in a significant underestimation of the active force generation required for pressure development and the power requirements for ejection. Prior studies relating muscle work and power to ventricular oxygen consumption should be re-examined in this light.


Author(s):  
Narmin B. Hushmandi ◽  
Per Askebjer ◽  
Magnus Genrup

Abstract Despite a wealth of sophisticated CFD-methods, most designs are still based on one-dimensional and two-dimensional inviscid analytical tools. In such methods, realistic loss and angle assessment are indeed critical in order to arrive at correct loading, flow coefficient and reaction. The selected values are normally retained through the detailed design sequence for each iteration. This means that the throat sizing and hence the gauge angle is largely based on the early design work within the through-flow environment. Even one-degree error in angle estimation will turn into a rather large capacity error. For most designs, the exchange rate between capacity and gauge angle is on the order of 3–5 percent, per degree exit angle. In a previous publication, a methodology and equations were presented to assess the exit flow in an axial turbine blade row by Mamaev in Russian nomenclature and the tangential coordinate system. The approach, provided a unified and flow-physics based method for assessing exit angles from the geometry features like gauge angle, uncovered turning and flow features like Laval number, etc. Analysis of those formulas showed good agreement with physical flow pattern in real cascades for sub and transonic blade cascades. In this work, the same basic principal procedure is followed by employing the more international agreed nomenclature of blades such as an axial reference plane and Mach number. In the current work, the one-dimensional analysis results were compared with the three dimensional numerical modelling of a full annulus two-stage turbine. Analysis of the results showed the inherent unsteadiness specially outside the rotor blade cascades, however, comparison of the mass averaged exit angle with the one dimensional analysis showed satisfactory agreement.


1999 ◽  
Vol 36 (02) ◽  
pp. 102-112
Author(s):  
Michael D. A. Mackney ◽  
Carl T. F. Ross

Computational studies of hull-superstructure interaction were carried out using one-, two-and three-dimensional finite element analyses. Simplification of the original three-dimensional cases to one- and two-dimensional ones was undertaken to reduce the data preparation and computer solution times in an extensive parametric study. Both the one- and two-dimensional models were evaluated from numerical and experimental studies of the three-dimensional arrangements of hull and superstructure. One-dimensional analysis used a simple beam finite element with appropriately changed sections properties at stations where superstructures existed. Two-dimensional analysis used a four node, first order quadrilateral, isoparametric plane elasticity finite element, with a corresponding increase in the grid domain where the superstructure existed. Changes in the thickness property reflected deck stiffness. This model was essentially a multi-flanged beam with the shear webs representing the hull and superstructure sides, and the flanges representing the decks One-dimensional models consistently and uniformly underestimated the three-dimensional behaviour, but were fast to create and run. Two-dimensional models were also consistent in their assessment, and considerably closer in predicting the actual behaviours. These models took longer to create than the one-dimensional, but ran in very much less time than the refined three-dimensional finite element models Parametric insights were accomplished quickly and effectively with the simplest model and processor, but two-dimensional analyses achieved closer absolute measure of the displacement behaviours. Although only static analysis with simple loading and support conditions were presented, it is believed that similar benefits would be found for other loadings and support conditions. Other engineering components and structures may benefit from similarly judged simplification using one- and two-dimensional models to reduce the time and cost of preliminary design.


1992 ◽  
Vol 7 (1) ◽  
pp. 30-36 ◽  
Author(s):  
David J. Grimshaw

Many academic and practical traditions have been brought to bear upon the field of business information systems in an attempt to understand a rapidly changing subject. The insights provided by traditional disciplines to an essentially multi-disciplinary subject is essential and very healthy. However, there is a danger of proliferating many different, overlapping frameworks of information systems. There is a need to review the frameworks and suggest a way of integrating several approaches. The future research effort depends upon a consistent set of data being available and discussed. This paper reviews previous frameworks used to promote the understanding and discussion of information systems. The one-dimensional approach is rejected in favour of a three-dimensional approach built around three basic questions characterized as the three Ts. What tasks does the information system have to perform? What technology can best deliver the systems? In what timeframe are we operating? The paper concludes by suggesting an integrated taxonomy, based on the three Ts as the basis for future research and discussion.


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