193 research outputs found
A numerical comparison between degenerate parabolic and quasilinear hyperbolic models of cell movements under chemotaxis
We consider two models which were both designed to describe the movement of
eukaryotic cells responding to chemical signals. Besides a common standard
parabolic equation for the diffusion of a chemoattractant, like chemokines or
growth factors, the two models differ for the equations describing the movement
of cells. The first model is based on a quasilinear hyperbolic system with
damping, the other one on a degenerate parabolic equation. The two models have
the same stationary solutions, which may contain some regions with vacuum. We
first explain in details how to discretize the quasilinear hyperbolic system
through an upwinding technique, which uses an adapted reconstruction, which is
able to deal with the transitions to vacuum. Then we concentrate on the
analysis of asymptotic preserving properties of the scheme towards a
discretization of the parabolic equation, obtained in the large time and large
damping limit, in order to present a numerical comparison between the
asymptotic behavior of these two models. Finally we perform an accurate
numerical comparison of the two models in the time asymptotic regime, which
shows that the respective solutions have a quite different behavior for large
times.Comment: One sentence modified at the end of Section 4, p. 1
Asymptotic behavior of smooth solutions for partially dissipative hyperbolic systems with a convex entropy
We study the asymptotic time behavior of global smooth solutions to general
entropy dissipative hyperbolic systems of balance law in m space dimensions,
under the Shizuta-Kawashima condition. We show that these solutions approach
constant equilibrium state in the Lp-norm at a rate O(t^(-m/2(1-1/p))), as t
tends to , for p in [min (m,2),+ \infty]. Moreover, we can show that we
can approximate, with a faster order of convergence, theconservative part of
the solution in terms of the linearized hyperbolic operator for m >= 2, and by
a parabolic equation in the spirit of Chapman-Enskog expansion. The main tool
is given by a detailed analysis of the Green function for the linearized
problem
A hyperbolic model of chemotaxis on a network: a numerical study
In this paper we deal with a semilinear hyperbolic chemotaxis model in one
space dimension evolving on a network, with suitable transmission conditions at
nodes. This framework is motivated by tissue-engineering scaffolds used for
improving wound healing. We introduce a numerical scheme, which guarantees
global mass densities conservation. Moreover our scheme is able to yield a
correct approximation of the effects of the source term at equilibrium. Several
numerical tests are presented to show the behavior of solutions and to discuss
the stability and the accuracy of our approximation
A Discrete Kinetic Approximation of Entropy Solutions to Multidimensional Scalar Conservation Laws
AbstractWe present a new relaxation approximation to scalar conservation laws in several space variables by means of semilinear hyperbolic systems of equations with a finite number of velocities. Under a suitable multidimensional generalization of the Whitham relaxation subcharacteristic condition, we show the convergence of the approximated solutions to the unique entropy solution of the equilibrium Cauchy problem
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