SOLENOIDAL LIPSCHITZ TRUNCATION FOR PARABOLIC PDEs

Prandtl-Eyring fluids in 2D by means of solenoidal Lipschitz truncation

We prove the existence of weak solutions with homogeneous boundary data for the following equations of Navier-Stokes type equations divσ + f = ∇π + (∇u)u, where u : R ⊃ Ω → R is the velocity field satisfying div u = 0 and f : Ω→ R and π : Ω→ R are the external volume forces resp. the pressure. In order to model the behaviour of Prandtl-Eyring fluids we assume the validity of the stress-strain r...

Multirate Numerical Integration for Parabolic PDEs

To solve PDE problems with different time scales that are localized in space, multirate time integration is examined. This technique enables one to use large time steps for slowly time-varying spatial regions, and small steps for rapidly varying ones. Multirate time stepping is coupled with the local uniform grid refinement and provides a robust and efficient method for the target problem class...

Infinite dimensional backstepping for nonlinear parabolic PDEs

Completion of overdetermined parabolic PDEs

In this paper we apply methods of commutative algebra to analysis of systems of PDEs. More precisely, we show that systems which are parabolic in a generalized sense are equivalent to certain completed systems which are parabolic in the standard sense. We also propose a constructive method to get this completion, and Gröbner basis methods, via symbol modules of the systems, play a central role ...

Homogenization of periodic semilinear parabolic degenerate PDEs

In this paper a second order semilinear parabolic PDE with rapidly oscillating coefficients is homogenized. The novelty of our result lies in the fact that we allow the second order part of the differential operator to be degenerate in some part of Rd . Our fully probabilistic method is based on the deep connection between PDEs and BSDEs and the weak convergence of a class of diffusion processe...