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Displaying 21 –
40 of
154
This paper presents a model based on spectral hyperviscosity for the
simulation of 3D turbulent incompressible flows. One particularity of this
model is that the hyperviscosity is active only at the short velocity scales,
a feature which is reminiscent of Large Eddy Simulation models.
We propose a Fourier–Galerkin approximation of the perturbed
Navier–Stokes equations and we show that, as the cutoff wavenumber
goes to infinity, the solution of the model
converges (up to subsequences) to a weak...
We study the boundary layer approximation of the, already classical, mathematical model which describes the discharge of a laminar hot gas in a stagnant colder atmosphere of the same gas. We start by proving the existence and uniqueness of solutions of the nondegenerate problem under assumptions implying that the temperature T and the horizontal velocity u of the gas are strictly positive: T ≥ δ > 0 and u ≥ ε > 0 (here δ and ε are given as boundary conditions in the external atmosphere)....
We consider a 2D mathematical model describing the motion of a solution of surfactants submitted to a high shear stress in a CouetteTaylor system. We are interested in a stabilization process obtained thanks to the shear. We prove that, if the shear stress is large enough, there exists global in time solution for small initial data and that the solution of the linearized system (controlled by a nonconstant parameter) tends to 0 as goes to infinity. This explains rigorously some experiments.
We consider a 2D mathematical model describing the motion of a
solution of surfactants submitted to a high shear stress in a
Couette-Taylor system. We are interested in a stabilization process
obtained thanks to the shear. We prove that, if the shear stress is
large enough, there exists global in time solution for small
initial data and that the solution
of the linearized system (controlled by a nonconstant parameter) tends
to 0 as t goes to infinity. This
explains rigorously some experiments.
...
In this article, we wish to investigate the behavior of a two-layer turbulence model from the mathematical point of view, as this model is useful for the near-wall treatment in numerical simulations. First, we explain the difficulties inherent in the model. Then, we present a new variable that enables the mathematical study. Due to a problem of definition of the turbulent viscosity on the wall boundary, we consider an alternative version of the original equation. We show that some physical aspects...
In this article, we wish to investigate the behavior of a two-layer k - ε
turbulence model from the mathematical point of view, as this model is useful for the near-wall treatment in numerical simulations.
First, we explain the difficulties inherent in the
model. Then, we present a new variable θ that enables the mathematical study. Due to a problem of definition of the turbulent
viscosity on the wall boundary, we consider an alternative version of the original equation. We show that some physical...
This article is devoted to the construction of a mathematical model describing the early
formation of atherosclerotic lesions. The early stage of atherosclerosis is an
inflammatory process that starts with the penetration of low density lipoproteins in the
intima and with their oxidation. This phenomenon is closely linked to the local blood flow
dynamics. Extending a previous work [5] that was mainly restricted to a
one-dimensional setting, we couple...
A distributed-parameter (one-dimensional) anatomically detailed model for the arterial network of the arm is developed in order to carry out hemodynamics simulations. This work focuses on the specific aspects related to the model set-up. In this regard, stringent anatomical and physiological considerations have been pursued in order to construct the arterial topology and to provide a systematic estimation of the involved parameters. The model comprises 108 arterial segments, with 64 main arteries...
In this paper, we propose a mathematical model for flow and transport processes of diluted solutions in domains separated by a leaky semipermeable membrane. We formulate transmission conditions for the flow and the solute concentration across the membrane which take into account the property of the membrane to partly reject the solute, the accumulation of rejected solute at the membrane, and the influence of the solute concentration on the volume flow, known as osmotic effect. The model is solved...
In this contribution we propose a model of coupled heat and moisture transport in variable saturated deformed porous media. Solution of this model provides temperature, moisture content and strain as a function of space and time. We present the detailed description of the model and a~numerical illustrative example.
We study the time-harmonic acoustic scattering in a duct in presence of a flow and of a discontinuous impedance boundary condition. Unlike a continuous impedance, a discontinuous one leads to still open modeling questions, as in particular the singularity of the solution at the abrupt transition and the choice of the right unknown to formulate the scattering problem. To address these questions we propose a mathematical approach based on variational formulations set in weighted Sobolev spaces. Considering...
The swelling and shrinkage of biological tissues are modelled by a four-component mixture theory [J.M. Huyghe and J.D. Janssen, Int. J. Engng. Sci.35 (1997) 793–802; K. Malakpoor, E.F. Kaasschieter and J.M. Huyghe, Mathematical modelling and numerical solution of swelling of cartilaginous tissues. Part I: Modeling of incompressible charged porous media.
ESAIM: M2AN41 (2007) 661–678]. This theory results in a coupled system of nonlinear parabolic differential equations together with an algebraic...
The swelling and shrinkage of biological tissues are modelled by a four-component mixture theory in which a deformable and charged porous medium is saturated with a fluid with dissolved ions. Four components are defined: solid, liquid, cations and anions. The aim of this paper is the construction of the Lagrangian model of the four-component system. It is shown that, with the choice of Lagrangian description of the solid skeleton, the motion of the other components can be described in terms of...
Currently displaying 21 –
40 of
154