Kinetic boundary layers, numerical simulations

An immersed boundary method for numerical simulations of boundary layers with roughness

Kinetic Boundary Layers and Fluid-Kinetic Coupling in Semiconductors

The semiconductor Boltzmann equation with elastic collisions as the dominating scattering eeects is considered. For the corresponding uid limit, the spherical harmonics expansion model, kinetic boundary layers are analyzed and higher order accurate boundary conditions are constructed. In a further step, boundary value problems for the energy transport model and the drift-diiusion model are deri...

Numerical boundary layers for hyperbolicsystems in 1

The aim of this paper is to investigate the stability of boundary layers which appear in numerical solutions of hyperbolic systems of conservation laws in one space dimension on regular meshes. We prove stability under a size condition for Lax Friedrichs type scheme and inconditionnal stability in the scalar case. Examples of unstable boundary layers are also given.

Direct Numerical Simulations of Turbulent Boundary Layers on High Performance Computers

Direct Numerical Simulations (DNS) of turbulent zero pressure gradient boundary layers have been performed on two high performance computers with di erent architectures. The one, a Cray T3E-900, is a massively parallel computer (HLRS computing center, Stuttgart/Germany). The other, a Fujitsu VPP700, is a Vector-parallel computer (Leibniz Computing Center, Munich/Germany). Both computers are wel...

Numerical Discovery of Drifting High-frequency QPOs in Global Simulations of Magnetic Boundary Layers

We report on the numerical discovery of quasi-periodic oscillations (QPOs) associated with accretion through a non-axisymmetric magnetic boundary layer, when two ordered equatorial streams form and rotate synchronously at approximately the angular velocity of the inner disk. This type of matter flow and QPO features appear in the unstable regime when the magnetosphere is small and the disk rota...