The gas composition surrounding a catalytic sample has direct impact on its surface structure, which is essential when in situ investigations of model catalysts are performed. Herein a study of the gas phase close to a Pd(110) surface during CO oxidation under semirealistic conditions is presented. Images of the gas phase, provided by planar laser-induced fluorescence, clearly visualize the for...

In previous chapters boundary layers were evident as thin layers across which thermal, dynamic, and material properties of a free interior flow make a transition to their boundary values and/or boundary fluxes. In those cases the thinness of the boundary layer was typically a statement of the smallness of the relevant diffusivity; e.g., the depth h of the laminar Ekman boundary layer scales as ...

We model the superfluid flow of liquid helium over a real surface, derived from a wire used to experimentally generate turbulence (profiled by atomic force microscopy). We employ large-scale, microscopically-resolved numerical simulations of the Gross-Pitaevskii equation to find that vortices nucleate predominantly from the sharpest features in the surface, and drive the formation of a complex ...

This paper deals with the homogenization of elliptic systems with Dirichlet boundary condition, when the coefficients of both the system and the boundary data are ε-periodic. We show that, as ε → 0, the solutions converge in L2 with a power rate in ε, and identify the homogenized limit system. Due to a boundary layer phenomenon, this homogenized system depends in a non trivial way on the bounda...

This article summarizes our present understanding of the physical behavior of two-dimensional turbulent separated flows, which occur due to adverse pressure gradients around streamlined and bluff bodies. The physical behavior of turbulence is flow dependent, so detailed experimental infor­ mation is needed for understanding such flows and modeling their physics for calculation methods. An earli...

Sea ice is in almost constant motion in response to wind, ocean currents, and forces transmitted within the ice cover itself, thus there is nearly always a zone of sheared Sow between the ice and underlying, undisturbed ocean where turbulence transports momentum, heat, salt, and other contaminants vertically. The zone in which these turbulent Suxes occur, which can span from a few to hundreds o...

In this study, a mathematical model is introduced to simulate the coupled heat transfer equation and Stefan condition occurring in moving boundary problems such as the solidification process in the continuous casting machines. In the continuous casting process, there exists a two-phase Stefan problem with moving boundary. The control-volume finite difference approach together with the boundary ...

Two models of recrystallization are proposed taking into account the convective flux impurity exchange between polycrystalline and thin-film coating. The special boundary modes described by single-phase two-phase Stefan problems with condition at coated surface containing term. exact solutions formulated corresponding to grain-boundary concentration impurities obtained. detail theoretical analy...