A 2D nonlinear model for the electrical potential in the edge plasma in a tokamak generates a stiff problem due to the low resistivity in the direction parallel to the magnetic field lines. An asymptotic-preserving method based on a micromacro decomposition is studied in order to have a well-posed problem, even when the parallel resistivity goes to 0. Numerical tests with a finite difference sc...

In this talk, we present some joint work with current and former colleagues at Penn State (C. Liu, P. Yu and Y. Hyon) on moment closure approximations of multiscale complex fluid models. Moment closure not only provides a computationally feasible approach to simulate many multiscale phenomena but also offers insight to the understanding of the underlying physical processes. We will discuss some...

Network control mechanisms in networks can be categorized by the time scales on which an individual control takes effect and they form a layered structure with respect to the time scales. In high-speed networks, the processing speed of each node is high but the propagation delay is the same as in slower networks, because it is constrained by the speed of light. So, the framework of network cont...

This paper deals with the interaction between microstructures and appearance or persistence of singular configurations in Cauchy problem for two-dimensional model incompressible micropolar fluids. We analyze case null angular viscosity initial data, including possibility vortex sheets measures as data Morrey spaces. Through integral techniques we establish existence weak solutions local global ...

This paper collects the efforts done in our previous works [8],[11],[10] to build a robust multiscale kinetic-fluid solver. Our scope is to efficiently solve fluid dynamic problems which present non equilibrium localized regions that can move, merge, appear or disappear in time. The main ingredients of the present work are the followings ones: a fluid model is solved in the whole domain togethe...

We show existence and uniqueness of a stationary state for a kinetic Fokker-Planck equation modeling the fibre lay-down process in the production of non-woven textiles. Following a micromacro decomposition, we use hypocoercivity techniques to show exponential convergence to equilibrium with an explicit rate assuming the conveyor belt moves slow enough. This work is an extention of [2], where th...