Carlos Arturo Vega

We propose an entropy-stable numerical scheme for an augmented one-dimensional blood flow model by constructing an explicit diffusion operator independent of the reconstruction method used for the scaled entropy variables. The diffusion term plays an important role in entropy-stable schemes, i.e., schemes satisfying a discrete entropy inequality. In general, the diffusion operator involves a diffusion matrix that depends on the scaled right eigenvectors and on the reconstruction of the scaled variables. We derive a simple, explicit expression for this operator that avoids computing the full set of scaled eigenvectors. The performance of the scheme is assessed through numerical experiments, focusing on Riemann problems, which confirm its ability to capture shock waves accurately and provide numerical evidence of entropy decay for non-smooth solutions.

In this work, an entropy-stable and well-balanced numerical scheme for a one-dimensional blood flow model is presented. Such a scheme was obtained from an explicit entropy-conservative flux along with a second-order discretisation of the source term by using centred finite differences. We prove that the scheme is entropy-stable and preserves steady-state solutions. In addition, some numerical examples are included to test the performance of the proposed scheme.

In this work, an entropy-stable and well-balanced numerical scheme for a one-dimensional blood flow model is presented. Such scheme is obtained from an explicit entropy conservative flux along with a second order discretization of the source term by using centered finite differences. We prove that the scheme is entropy-stable and preserves steady-states solutions. In addition, some numerical examples are included to test the performance of the proposed scheme.

The aim of this paper is to derive a separable entropy for a one-dimensional reduced blood flow model, which will be used to treat the symmetrizability of the model in full generality and for constructing entropy conservative fluxes, which are one of the essential building blocks of designing entropy-stable schemes. Time discretization is conducted by implicit–explicit (IMEX) Runge–Kutta schemes, but solutions for nonlinear systems will not be required due to the particular form of the source term. To validate the numerical schemes obtained, some numerical tests are presented.

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In this paper, the implementation of a spectral or characteristic-based fifth order WENO (Weighted Essentially Non-Oscillatory) scheme is described in detail along with an adaptive multiresolution technique for efficiently computing the numerical solution of a multi-class traffic flow model described mathematically by a nonlinear system of conservation laws. In [1] the authors considered the same problem but in a component-wise manner. More recently, [2] conducted numerical experiments by using characteristic-based schemes combined with AMR (Adaptive Mesh Refinement) strategy.

The sedimentation of a polydisperse suspension of small spherical particles dispersed in a viscous fluid, where particles belong to N species differing in size, can be described by a strongly coupled system of N scalar, nonlinear first‐order conservation laws for the evolution of the volume fractions. The hyperbolicity of this system is a property of theoretical importance because it limits the range of validity of the model and is of practical interest for the implementation of numerical methods. The present work, which extends the results of R. Bürger, R. Donat, P. Mulet, and C.A. Vega (SIAM Journal on Applied Mathematics 2010; 70:2186–2213), is focused on the fluxes corresponding to the models by Batchelor and Wen, Höfler and Schwarzer, and Davis and Gecol, for which the Jacobian of the flux is a rank‐3 or rank‐4 perturbation of a diagonal matrix. Explicit estimates of the regions of hyperbolicity of these models are derived via the approach of the so‐called secular equation (J. Anderson. Linear Algebra and Applications 1996; 246:49–70), which identifies the eigenvalues of the Jacobian with the poles of a particular rational function. Hyperbolicity of the system is guaranteed if the coefficients of this function have the same sign. Sufficient conditions for this condition to be satisfied are established for each of the models considered. Some numerical examples are presented. Copyright © 2012 John Wiley & Sons, Ltd.