scholarly journals Nonequilibrium thermodynamics and boundary conditions for reaction and transport in heterogeneous media

2018 ◽  
Vol 148 (19) ◽  
pp. 194114 ◽  
Author(s):  
Pierre Gaspard ◽  
Raymond Kapral
Keyword(s):  
Boundary Conditions ◽  
Heterogeneous Media ◽  
Nonequilibrium Thermodynamics

3D finite-difference dynamic-rupture modeling along nonplanar faults

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. SM123-SM137 ◽  
Author(s):  
Víctor M. Cruz-Atienza ◽  
Jean Virieux ◽  
Hideo Aochi
Keyword(s):  
Finite Difference ◽  
Boundary Conditions ◽  
Heterogeneous Media ◽  
Slip Rate ◽  
Quantitative Agreement ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Weight Functions ◽  
Dynamic Rupture ◽  
Fault Surface

Proper understanding of seismic emissions associated with the growth of complexly shaped microearthquake networks and larger-scale nonplanar fault ruptures, both in arbitrarily heterogeneous media, requires accurate modeling of the underlying dynamic processes. We present a new 3D dynamic-rupture, finite-difference model called the finite-difference, fault-element (FDFE) method; it simulates the dynamic rupture of nonplanar faults subjected to regional loads in complex media. FDFE is based on a 3D methodology for applying dynamic-rupture boundary conditions along the fault surface. The fault is discretized by a set of parallelepiped fault elements in which specific boundary conditions are applied. These conditions are applied to the stress tensor, once transformed into a local fault referenceframe. Numerically determined weight functions multiplying particle velocities around each element allow accurate estimates of fault kinematic parameters (i.e., slip and slip rate) independent of faulting mechanism. Assuming a Coulomb-like slip-weakening friction law, a parametric study suggests that the FDFE method converges toward a unique solution, provided that the cohesive zone behind the rupture front is well resolved (i.e., four or more elements inside this zone). Solutions are free of relevant numerical artifacts for grid sizes smaller than approximately [Formula: see text]. Results yielded by the FDFE approach are in good quantitative agreement with those obtained by a semianalytical boundary integral method along planar and nonplanar parabola-shaped faults. The FDFE method thus provides quantitative, accurate results for spontaneous-rupture simulations on intricate fault geometries.

scholarly journals Equivalent Boundary Conditions for Heterogeneous Acoustic Media

2014 ◽  
Vol 15 (3) ◽  
pp. 301
Author(s):  
Manuela Longoni De Castro ◽  
Julien Diaz ◽  
Victor Perón
Keyword(s):  
Boundary Conditions ◽  
Seismic Waves ◽  
Heterogeneous Media ◽  
Absorbing Boundary Conditions ◽  
Computational Domain ◽  
Absorbing Boundary ◽  
Equivalent Boundary ◽  
Artificial Boundaries ◽  
Acoustic Media ◽  
Propagation Of Waves

In this work, we have worked on possibilities to model artificial boundaries needed in the simulation of wave propagation in acoustic heterogeneous media.  Our motivation is to restrict the computational domain in the simulation of seismic waves that are propagated from the earth and transmitted to the stratified heterogeneous media composed by ocean and atmosphere. Two possibilities were studied and compared in computational tests: the use of absorbing boundary conditions on an artificial boundary in the atmosphere layer and the elimination of the atmosphere layer using an equivalent boundary condition that mimics the propagation of waves through the atmosphere. <br />

RADIATION BOUNDARY CONDITIONS FOR VERTICALLY HETEROGENEOUS ACOUSTIC MEDIA

1993 ◽  
Vol 01 (03) ◽  
pp. 321-333 ◽  
Author(s):  
GONGQIN LI ◽  
JOSEPH E. MURPHY ◽  
STANLEY A. CHIN-BING
Keyword(s):  
Boundary Conditions ◽  
Heterogeneous Media ◽  
Plane Waves ◽  
Reflection Coefficients ◽  
Radiation Boundary Conditions ◽  
Media Comparison ◽  
Acoustic Media ◽  
Radiation Boundary ◽  
Radiation Conditions ◽  
Effective Reflection Coefficient

Several radiation boundary conditions for inhomogeneous acoustic media are investigated. Previous investigators have developed various approximate radiation conditions and have studied their accuracy by calculating an effective reflection coefficient for plane waves incident on such radiating boundaries. In this paper, it is shown that effective reflection coefficients can be calculated for a class of parabolic approximations to the Helmholtz equation. These results are valid for vertically heterogeneous media. Comparison of these radiation conditions is given through numerical examples.

scholarly journals Influence of boundary conditions on time-reversal focusing through heterogeneous media

1998 ◽  
Vol 72 (20) ◽  
pp. 2511-2513 ◽  
Author(s):  
Mickaël Tanter ◽  
Jean-Louis Thomas ◽  
Mathias Fink
Keyword(s):  
Boundary Conditions ◽  
Time Reversal ◽  
Heterogeneous Media
Sign in / Sign up

Export Citation Format

Share Document