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...

Singular perturbation problems have been studied by many mathematicians. Since the approximate solutions of these problems are as the sum of internal solution (boundary layer area) and external ones, the formation or non-formation of boundary layers should be specified. This paper, investigates this issue for a singular perturbation problem including a first order differential equation with gen...

Deformation pattern of the northeastern part of the Iranian-Arabian collision zone (i.e., mainly Sanandaj-Sirjan Belt or Zone) is the main concern of this paper. Here, we investigate the stress distribution and displacement pattern of Eghlid-Deh Bid area as affected by the position of Zagros suture using a three dimensional mechanical model. The modeled area is located between the Zagros Thrust...