REPORTRAPPORT Entropy conditions for heterogeneity induced shocks in two-phase flow problems Abstract We study two-phase ow in a porous medium with piecewise smooth permeability. If capillary forces can not be neglected, the ow problem is parabolic. Without capillary forces this problem degenerates to a hyperbolic conservation law with a discontinuous ux function. The solution for this problem ...

From the physical point of view a shock wave is defined by an abrupt, nearly discontinuous change in pressure and by having a velocity that is higher than the speed of sound in the medium it propagates [1]. A typical pressure profile of a focused shockwave used for therapeutic purposes is shown in fig. 1. Generally a shock wave can be described as a single pulse with a wide frequency range (fro...

the Interaction of Syntax, Semantics and Pragmatics by Kordula De Kuthy, published by CSLI Publications. ©2002 by CSLI Publications. All rights reserved. This text may be used and shared in accordance with the fair-use provisions of U.S. copyright law, and it may be archived and redistributed in electronic form, provided that this entire notice, including copyright information, is carried and p...

We present a hybrid continuous and discontinuous Galerkin spectral element approximation that leverages the advantages of each approach. The is used on interior faces where equation properties are continuous. A at physical boundaries if there jump in face. uses split form equations two-point fluxes to ensure stability for unstructured quadrilateral/hexahedral meshes with curved elements. also c...

A time stable discretization is derived for the second-order wave equation with discontinuous coefficients. The discontinuity corresponds to inhomogeneity in the underlying medium and is treated by splitting the domain. Each (homogeneous) sub domain is discretized using narrow-diagonal summation by parts operators and, then, patched to its neighbors by using a penalty method, leading to fully e...

We have constructed reliable finite difference methods for approximating the solution to Maxwell’s equations using accurate discrete analogs of differential operators that satisfy the identities and theorems of vector and tensor calculus in discrete form. The numerical approximation does not have spurious modes and mimics many fundamental properties of the underlying physical problem including ...

Thermomonospora curvata produces an extracellular alpha-amylase. Maximal amylase production by cultures in a starch-mineral salts medium occurred at pH 7.5 and 53 degrees C. The crude enzyme was unstable to heating (65 degrees C) at pH 4 to 6, and was activated when heated at pH 8. The enzyme was purified 66-fold with a 9% yield and appeared homogeneous on discontinuous gel electrophoresis. The...

This paper deals with the computation of two-phase flows in a porous medium, with two main objectives. First of all, we will present a new multi-dimensional well-balanced scheme, with its advantages and drawbacks. Furthermore, we will compare results of the porous model with approximations obtained with a full two-dimensional computation, where all obstacles have been taken into account in the ...

Electrically conductive roller-compacted concrete (ERCC) is a novel functional material, which can solve the problems of low efficiency artificial snow removal and deicing on expressway airport runway difficulty in temperature control dam engineering structures. In this study, we designed ERCC conducted an experimental study numerical simulations ERCC. The improvement mechanism su...

We consider time domain acoustic scattering from a penetrable medium with a variable sound speed. This problem can be reduced to solving a time domain volume Lippmann-Schwinger integral equation. Using convolution quadrature in time and trigonometric collocation in space we can compute an approximate solution. We prove that the time domain Lippmann-Schwinger equation has a unique solution and p...