Features of wave propagation in the sand of different saturation

2011 ◽  
Vol 8 (1) ◽  
pp. 25-38
Author(s):  
A.T. Akhmetov ◽  
S.V. Lukin ◽  
D.M. Balapanov ◽  
S.F. Urmancheev ◽  
N.M. Gumerov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Porous Medium ◽  
Porous Media ◽  
Wave Propagation ◽  
Water Saturation ◽  
Weak Shock ◽  
Capillary Forces ◽  
Theoretical Studies ◽  
Longitudinal Waves ◽  
Experimental And Theoretical Studies

There are the results of experimental and theoretical studies on the propagation of weak shock waves in the wet sand at different water saturation. There are mathematical model and numerical analysis of propagation of pressure pulses in porous media, taking into account capillary forces. Non-monotonic dependence of the amplitude of the wave resulting in a wet porous medium vs. the degree of water saturation is installed. The evolution of the fast, slow and filtration waves depends on the saturation of the system with water is analyzed. The influence of capillary forces on the propagation of longitudinal waves is evaluated.

Experimental and Theoretical Studies of Flocculated Asphaltene Deposition From Oil in Porous Media

2010 ◽  
Author(s):  
Ali Rezaian ◽  
Amin Kordestany ◽  
Mohammad Jamialahmadi ◽  
Jamshid Moghadasi ◽  
Mohammad Yousefi Khoshdaregi ◽  
...  
Keyword(s):  
Porous Media ◽  
Theoretical Studies ◽  
Asphaltene Deposition ◽  
Experimental And Theoretical Studies

Mathematical Formulation of the Global Coefficients of Transmission and Reflection of Ultrasonic Waves in Bi-Phase Porous Medium

2015 ◽  
Vol 1101 ◽  
pp. 471-479
Author(s):  
Georges Freiha ◽  
Hiba Othman ◽  
Michel Owayjan
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Wave Propagation ◽  
Mathematical Formulation ◽  
Ultrasonic Waves ◽  
Ultrasonic Wave Propagation ◽  
Local Coefficients ◽  
Important Field ◽  
New Formulation ◽  
Transmission And Reflection

The study of signals propagation inside porous media is an important field especially in the biomedical research related to compact bones. The purpose of this paper is to determine a mathematical formulation of the global coefficients of transmission and reflection of nondestructive ultrasonic waves in any bi-phase porous medium. Local coefficients of transmission and reflection on the interface of the porous medium will be determined based on a study of boundary conditions. The behavior of different waves inside the porous medium will be developed so that we can derive a new formulation of global coefficients that takes interior phenomena into consideration. Results are found independently of the geometrical and physical characteristics of the medium. Note that this study is based on normal incident ultrasonic wave propagation.

VIBRODIAGNOSTICS OF HINGE ELEMENTS CAR SUSPENSION

2020 ◽  
Vol 71 (4) ◽  
pp. 3-10
Author(s):  
A.Yu. RODICHEV ◽  
◽  
M.D. TEBEKIN ◽  
A.V. GORIN ◽  
S.V. KOLPAKOVA ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Technical Condition ◽  
Theoretical Studies ◽  
Ball Joint ◽  
Theoretical Methods ◽  
Design Scheme ◽  
Car Suspension ◽  
Analysis Of Failures ◽  
Experimental And Theoretical Studies

The article contains an analysis of failures of articulated elements of automotive equipment. The paper presents a mathematical model for changing the technical condition of the ball joint of automotive vehicles. A design scheme is proposed, assumptions and limitations for a mathematical model are determined. During the work, experimental and theoretical studies were carried out. To assess the reliability of the results obtained by theoretical methods, an experimental study was car-ried out on the developed installation using vibration methods.

Modeling of magmatic channel formation in thin lithosphere areas

2020 ◽  
Author(s):  
Yuri Perepechko ◽  
Konstantin Sorokin ◽  
Georgiy Vasilyev
Keyword(s):  
Mathematical Model ◽  
Porous Medium ◽  
Porous Media ◽  
Saturated Porous Medium ◽  
High Stress ◽  
Marked Change ◽  
Porous Matrix ◽  
Small Scale ◽  
Magma Intrusion ◽  
Magma Flow

<p>The aim of the research is to construct a mathematical model of the formation of a fracture system in magma intrusion in the permeable zones of the lithosphere and on this basis to study the formation of magmatic channels in the lithosphere and crust. The lithosphere substrate is modeled by a saturated porous medium in which the processes of small-scale destruction in the mantle magma intrusion lead to the formation of faults and, consequently, to a magmatic channel. Destruction and occurrence of micro-fracture fields can be associated with both magma flow and external seismic effect leading to the rock breaking. The process of small-scale destruction is described within the framework of the dynamics of the elastoplastic fracture-porous medium and causes variations in the rheological properties of the lithosphere substrate. A feature of this process is the destruction substrate in the compression zone represented by a narrow area with a sharply changing concentration of micro-fractures. The micro-fracture accumulation provides the conversion of the broken area into a macro-fissure. The elastoplastic porous matrix in the destruction zone contains both broken and intact substrate, the relative content of which is determined by relaxation of deformations, the speed of which depends on stress and yield stress point according to the power law. The obtained mathematical model provides investigation of currents in fractured-porous media and their effect on the small-scale destruction. Based on the TVD-Runge Kutta method numerical simulation of the compressible fluid infiltration into the fracture-porous permeable channel has shown that stresses in the compression domain can reach stress limits of breaking and result in fracture formation. Change in relaxation time does not result in a marked change in stress fields. The concentration of maximum stresses is observed in the channel center leading to an increase in its fracture porosity. The computational results show the appearance of high stress values in the compression domain in the process of a liquid phase injection, for instance, magma, into a low-permeable fracture-porous layer. The introduction of the destruction criterion will help to associate the occurrence of such regions to the local breaking of the porous matrix. Thus, the proposed micro-fracture generation mechanism can be used to describe the formation of fracture or channels in micro-fracture porous media. Work is done on state assignment of IGM SB RAS with partial support from the Russian Foundation for Basic Research, grants No. 16-29-15131, 19-05-00788.</p>

Two-phase gravity currents in porous media

2011 ◽  
Vol 678 ◽  
pp. 248-270 ◽  
Author(s):  
MADELEINE J. GOLDING ◽  
JEROME A. NEUFELD ◽  
MARC A. HESSE ◽  
HERBERT E. HUPPERT
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Fluid Flow ◽  
Current Model ◽  
Gravity Current ◽  
Capillary Forces ◽  
Gravity Currents ◽  
Flow In Porous Media ◽  
Two Phase ◽  
Residual Trapping

We develop a model describing the buoyancy-driven propagation of two-phase gravity currents, motivated by problems in groundwater hydrology and geological storage of carbon dioxide (CO2). In these settings, fluid invades a porous medium saturated with an immiscible second fluid of different density and viscosity. The action of capillary forces in the porous medium results in spatial variations of the saturation of the two fluids. Here, we consider the propagation of fluid in a semi-infinite porous medium across a horizontal, impermeable boundary. In such systems, once the aspect ratio is large, fluid flow is mainly horizontal and the local saturation is determined by the vertical balance between capillary and gravitational forces. Gradients in the hydrostatic pressure along the current drive fluid flow in proportion to the saturation-dependent relative permeabilities, thus determining the shape and dynamics of two-phase currents. The resulting two-phase gravity current model is attractive because the formalism captures the essential macroscopic physics of multiphase flow in porous media. Residual trapping of CO2 by capillary forces is one of the key mechanisms that can permanently immobilize CO2 in the societally important example of geological CO2 sequestration. The magnitude of residual trapping is set by the areal extent and saturation distribution within the current, both of which are predicted by the two-phase gravity current model. Hence the magnitude of residual trapping during the post-injection buoyant rise of CO2 can be estimated quantitatively. We show that residual trapping increases in the presence of a capillary fringe, despite the decrease in average saturation.

scholarly journals Wave Equations of Porous Media Saturated With Two Immiscible Fluids Based on the Volume Averaging Method

2021 ◽  
Vol 9 ◽  
Author(s):  
Fansheng Xiong ◽  
Jiawei Liu ◽  
Zhenwei Guo ◽  
Jianxin Liu
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Wave Propagation ◽  
Wave Equations ◽  
Coefficient Matrix ◽  
Immiscible Fluids ◽  
Original Model ◽  
Governing Equations ◽  
Improved Model ◽  
Dispersion And Attenuation

Simulating and predicting wave propagation in porous media saturated with two fluids is an important issue in geophysical exploration studies. In this work, wave propagation in porous media with specified structures saturated with two immiscible fluids was studied, and the main objective was to establish a wave equation system with a relatively simple structure. The wave equations derived by Tuncay and Corapcioglu were analyzed first. It was found that the coefficient matrix of the equations tends to be singular due to the inclusion of a small parameter that characterizes the effect of capillary stiffening. Therefore, the previously established model consisting of three governing equations may be unstable under natural conditions. An improved model based on Tuncay and Corapcioglu’s work was proposed to ensure the nonsingularity of the coefficient matrix. By introducing an assumption in which one fluid was completely wrapped by the other, the governing equation of the wrapped fluid was degenerated. In this way, the coefficient matrix of wave equations became nonsingular. The dispersion and attenuation prediction resulting from the new model was compared with that of the original model. Numerical examples show that although the improved model consists of only two governing equations, it can obtain a result similar to that of the original model for the case of a porous medium containing gas and water, which simplifies the complexity of the calculations. However, in a porous medium with oil and water, the predictions of dispersion and attenuation produced by the original model obviously deviate from the normal trend. In contrast, the results of the improved model exhibit the correct trend with a smooth curve. This phenomenon shows the stability of the improved model and it could be used to describe wave propagation dispersions and attenuations of porous media containing two immiscible fluids in practical cases.

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