Browsing by Author "Feireisl, Eduard"

Now showing 1 - 6 of 6
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    Analysis of a diffuse interface model of multispecies tumor growth
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2015) Dai, Mimi; Feireisl, Eduard; Rocca, Elisabetta; Schimperna, Giulio
    We consider a diffuse interface model for tumor growth recently proposed in [3]. In this new approach sharp interfaces are replaced by narrow transition layers arising due to adhesive forces among the cell species. Hence, a continuum thermodynamically consistent model is introduced. The resulting PDE system couples four different types of equations: a Cahn-Hilliard type equation for the tumor cells (which include proliferating and dead cells), a Darcy law for the tissue velocity field, whose divergence may be different from 0 and depend on the other variables, a transport equation for the proliferating (viable) tumor cells, and a quasi-static reaction diffusion equation for the nutrient concentration. We establish existence of weak solutions for the PDE system coupled with suitable initial and boundary conditions. In particular, the proliferation function at the boundary is supposed to be nonnegative on the set where the velocity u satisfies u ypsilon 0, where ypsilon is the outer normal to the boundary of the domain. We also study a singular limit as the diffuse interface coefficient tends to zero.
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    Convergence and Error Analysis of Compressible Fluid Flows with Random Data: Monte Carlo Method
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach, 2022) Feireisl, Eduard; Lukáčova-Medviďová, Mariá; She, Bangwei; Yuan, Yuhuan
    The goal of this paper is to study convergence and error estimates of the Monte Carlo method for the Navier-Stokes equations with random data. To discretize in space and time, the Monte Carlo method is combined with a suitable deterministic discretization scheme, such as a fnite volume method. We assume that the initial data, force and the viscosity coefficients are random variables and study both, the statistical convergence rates as well as the approximation errors. Since the compressible Navier-Stokes equations are not known to be uniquely solvable in the class of global weak solutions, we cannot apply pathwise arguments to analyze the random Navier-Stokes equations. Instead we have to apply intrinsic stochastic compactness arguments via the Skorokhod representation theorem and the Gyöngy-Krylov method. Assuming that the numerical solutions are bounded in probability, we prove that the Monte Carlo fnite volume method converges to a statistical strong solution. The convergence rates are discussed as well. Numerical experiments illustrate theoretical results.
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    Local Existence and Conditional Regularity for the Navier-Stokes-Fourier System Driven by Inhomogeneous Boundary Conditions
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach, 2024) Abbatiello, Anna; Basarić, Danica; Chaudhuri, Nilasis; Feireisl, Eduard
    We consider the Navier–Stokes–Fourier system with general inhomogeneous Dirichlet–Neumann boundary conditions. We propose a new approach to the local well-posedness problem based on conditional regularity estimates. By conditional regularity we mean that any strong solution belonging to a suitable class remains regular as long as its amplitude remains bounded. The result holds for general Dirichlet-Neumann boundary conditions provided the material derivative of the velocity field vanishes on the boundary of the physical domain. As a corollary of this result we obtain: Blow up criteria for strong solutions; Local existence of strong solutions in the optimal Lp - Lq framework; Alternative proof of the existing results on local well posedness.
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    Nonisothermal nematic liquid crystal flows with the Ball-Majumdar free energy
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2013) Feireisl, Eduard; Rocca, Elisabetta; Schimperna, Giulio; Zarnescu, Arghir
    In this paper we prove the existence of global in time weak solutions for an evolutionary PDE system modelling nonisothermal Landau-de Gennes nematic liquid crystal (LC) flows in three dimensions of space. In our model, the incompressible Navier-Stokes system for the macroscopic velocity u is coupled to a nonlinear convective parabolic equation describing the evolution of the Q-tensor Q, namely a tensor-valued variable representing the normalized second order moments of the probability distribution function of the LC molecules. The effects of the (absolute) temperature theta are prescribed in the form of an energy balance identity complemented with a global entropy production inequality. Compared to previous contributions, we can consider here the physically realistic singular configuration potential f introduced by Ball and Majumdar. This potential gives rise to severe mathematical difficulties since it introduces, in the Q-tensor equation, a term which is at the same time singular in Q and degenerate in theta. To treat it a careful analysis of the properties of f, particularly of its blow-up rate, is carried out.
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    On asymptotic isotropy for a hydrodynamic model of liquid crystals
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2014) Dai, Mimi; Feireisl, Eduard; Rocca, Elisabetta; Schimperna, Giulio; Schonbek, Maria E.
    We study a PDE system describing the motion of liquid crystals by means of the Q?tensor description for the crystals coupled with the incompressible Navier-Stokes system. Using the method of Fourier splitting, we show that solutions of the system tend to the isotropic state at the rate (1 + t)-β as t → ∞ for a certain β > 1/2 .
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    Regularity and energy conservation for the compressible Euler equations
    (Oberwolfach : Mathematisches Forschungsinstitut Oberwolfach, 2016) Feireisl, Eduard; Gwiazda, Piotr; Świerczewska-Gwiazda, Agnieszka; Wiedemann, Emil
    We give sufficient conditions on the regularity of solutions to the inhomogeneous incompressible Euler and the compressible isentropic Euler systems in order for the energy to be conserved. Our strategy relies on commutator estimates similar to those employed by P. Constantin et al. for the homogeneous incompressible Euler equations.