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101.
102.
103.
Jeremiah Rushchitsky 《Comptes Rendus Mecanique》2002,330(3):175-180
The problem of self-switching plane waves in elastic nonlinearly deformed materials is formulated. Reduced and evolution equations, which describe the interaction of two waves the power pumping wave and the faint signal wave are obtained. For the case of wave numbers matching the pumping and signal waves, a procedure of finding the exact solution of evolution equations is described. The solution is expressed by elliptic Jacobi functions. The existence of the power wave self-switching is shown and commented. To cite this article: J. Rushchitsky, C. R. Mecanique 330 (2002) 175–180. 相似文献
104.
V.A. Osinov 《Continuum Mechanics and Thermodynamics》1998,10(5):253-268
The paper deals with propagation of plane wave fronts in a solid with a non-linear relation between stress and deformation.
The objective is to calculate the distance that a wave front covers before it loses continuity. The formulae derived for a
general quasi-linear system of two equations are applied to the propagation of plane compression waves in dry and partially
saturated granular bodies. In the case of a saturated body with gas bubbles, the influence of gas and capillary pressure on
the stiffness of the body is taken into account. Numerical calculations relevant to soil mechanics are presented. For the
numerical calculations a constitutive equation of the hypoplasticity theory for granular materials has been used.
Received November 1, 1997 相似文献
105.
非线性水波Hamilton系统理论与应用研究进展 总被引:12,自引:0,他引:12
概述了辛几何理论与辛算法在Hamilton力学中的应用,综述非线性水波的Hamilton理论研究进展.阐述非线性水波Hamilton变分原理与方法的优越性与局限性,探讨KdV方程和BBM方程的Hamilton描述、对称性与守恒律,提出非线性水波Hamilton描述研究中有待进一步研究的问题和解法设想. 相似文献
106.
The method developed by Debiane and Kharif for the calculation of symmetric gravity-capillary waves on infinite depth is extended to the general case of non-symmetric solutions. We have calculated non-symmetric steady periodic gravity-capillary waves on deep water. It is found that they appear via bifurcations from a family of symmetric waves. On the other hand we found that the symmetry-breaking bifurcation of periodic steady class 1 gravity wave on deep water is possible when it approaches the limiting profile, if it is very weakly influenced by surface tension effects. To cite this article: R. Aider, M. Debiane, C. R. Mecanique 332 (2004). 相似文献
107.
考虑双层碳纳米管的层间范德华力,采用连续介质力学的波动理论,建立了双层碳纳米管中周向导波传播模型,研究周向导波的频散现象.通过与单层碳纳米管结果的比较表明,双层碳纳米管中周向导波的传播表现出更为明显的频散特性,出现更多的模态干涉现象,并发现在某些特殊频率处出现成对模态的消失与新启现象. 相似文献
108.
Although, the effects of ultrasonic irradiation on multiphase flow through porous media have been studied in the past few
decades, the physics of the acoustic interaction between fluid and rock is not yet well understood. Various mechanisms may
be responsible for enhancing the flow of oil through porous media in the presence of an acoustic field. Capillary related
mechanisms are peristaltic transport due to mechanical deformation of the pore walls, reduction of capillary forces due to
the destruction of surface films generated across pore boundaries, coalescence of oil drops due to Bjerknes forces, oscillation
and excitation of capillary trapped oil drops, forces generated by cavitating bubbles, and sonocapillary effects. Insight
into the physical principles governing the mobilization of oil by ultrasonic waves is vital for developing and implementing
novel techniques of oil extraction. This paper aims at identifying and analyzing the influence of high-frequency, high-intensity
ultrasonic radiation on capillary imbibition. Laboratory experiments were performed using cylindrical Berea sandstone and
Indiana limestone samples with all sides (quasi-co-current imbibition), and only one side (counter-current imbibition) contacting
with the aqueous phase. The oil saturated cores were placed in an ultrasonic bath, and brought into contact with the aqueous
phase. The recovery rate due to capillary imbibition was monitored against time. Air–water, mineral oil–brine, mineral oil–surfactant
solution and mineral oil-polymer solution experiments were run each exploring a separate physical process governing acoustic
stimulation. Water–air imbibition tests isolate the effect of ultrasound on wettability, capillarity and density, while oil–brine
imbibition experiments help outline the ultrasonic effect on viscosity and interfacial interaction between oil, rock and aqueous
phase. We find that ultrasonic irradiation enhances capillary imbibition recovery of oil for various fluid pairs, and that
such process is dependent on the interfacial tension and density of the fluids. Although more evidence is needed, some runs
hint that wettability was not altered substantially under ultrasound. Preliminary analysis of the imbibition recoveries also
suggests that ultrasound enhances surfactant solubility and reduce surfactant adsorption onto the rock matrix. Additionally,
counter-current experiments involving kerosene and brine in epoxy coated Berea sandstone showed a dramatic decline in recovery.
Therefore, the effectiveness of any ultrasonic application may strongly depend on the nature of interaction type, i.e., co-
or counter-current flow. A modified form of an exponential model was employed to fit the recovery curves in an attempt to
quantify the factors causing the incremental recovery by ultrasonic waves for different fluid pairs and rock types. 相似文献
109.
Mild-slope (MS) type equations are depth-integrated models, which predict under appropriate conditions refraction and diffraction of linear time-harmonic water waves. By using a streamfunction formulation instead of a velocity potential one, the complementary mild-slope equation (CMSE) was shown to give better agreement with exact linear theory compared to other MS-type equations. The main goal of this work is to extend the CMSE model for solving two-layer flow with a free-surface. In order to allow for an exact reference, an analytical solution for a two-layer fluid over a sloping plane beach is derived. This analytical solution is used for validating the results of the approximated MS-type models. It is found that the two-layer CMSE model performs better than the potential based one. In addition, the new model is used for investigating the scattering of linear surface water waves and interfacial ones over variable bathymetry. 相似文献
110.
We study the simultaneous one-dimensional flow of water and oil in a heterogeneous medium modelled by the Buckley-Leverett equation. It is shown both by analytical solutions and by numerical experiments that this hyperbolic model is unstable in the following sense: Perturbations in physical parameters in a tiny region of the reservoir may lead to a totally different picture of the flow. This means that simulation results obtained by solving the hyperbolic Buckley-Leverett equation may be unreliable.Symbols and Notation
f
fractional flow function varying withs andx
-
value off outsideI
-
value off insideI
-
local approximation off around¯x
-
f
–,f
+
values of
-
f
j
n
value off atS
j
n
andx
j
-
g
acceleration due to gravity [ms–2]
-
I
interval containing a low permeable rock
-
k
dimensionless absolute permeability
-
k
*
absolute permeability [m2]
-
k
c
*
characteristic absolute permeability [m2]
-
k
ro
relative oil permeability
-
k
rw
relative water permeability
-
L
*
characteristic length [m]
-
L
1
the space of absolutely integrable functions
-
L
the space of bounded functions
-
P
c
dimensionless capillary pressure function
-
P
c
*
capillary pressure function [Pa]
-
P
c
*
characteristic pressure [Pa]
-
S
similarity solution
-
S
j
n
numerical approximation tos(xj, tn)
-
S
1, S2,S
3
constant values ofs
-
s
water saturation
-
value ofs at
-
s
L
left state ofs (wrt.
)
-
s
R
right state ofs (wrt.
)
-
s
s for a fixed value of in Section 3
-
T
value oft
-
t
dimensionless time coordinate
-
t
*
time coordinate [s]
-
t
c
*
characteristic time [s]
-
t
n
temporal grid point,t
n=n t
-
v
*
total filtration (Darcy) velocity [ms–1]
-
W, , v
dimensionless numbers defined by Equations (4), (5) and (6)
-
x
dimensionless spatial coordinate [m]
-
x
*
spatial coordinate [m]
-
x
j
spatial grid piont,x
j=j x
-
discontinuity curve in (x, t) space
-
right limiting value of¯x
-
left limiting value of¯x
-
angle between flow direction and horizontal direction
- t
temporal grid spacing
- x
spatial grid spacing
-
length ofI
-
parameter measuring the capillary effects
-
argument ofS
-
o
dimensionless dynamic oil viscosity
- w
dimensionless dynamic water viscosity
-
c
*
characteristic viscosity [kg m–1s–1]
-
o
*
dynamic oil viscosity [kg m–1s–1]
-
w
*
dynamic water viscosity [k gm–1s–1]
-
o
dimensionless density of oil
-
w
dimensionless density of water
-
c
*
characteristic density [kgm–3]
-
o
*
density of oil [kgm–3]
-
w
*
density of water [kgm–3]
-
porosity
-
dimensionless diffusion function varying withs andx
-
*
dimensionless function varying with s andx
* [kg–1m3s]
-
j
n
value of atS
j
n
andx
j
This research has been supported by VISTA, a research cooperation between the Norwegian Academy of Science and Letters and Den norske stats oljeselskap a.s. (Statoil). 相似文献