A turbulent channel flow modified by the motion of discs that are free to rotate under action wall turbulence is studied numerically. The Navier-Stokes equations coupled nonlinearly with dynamical equation disc motion, which synthesizes fluid-flow boundary conditions and driven torque exerted wall-shear stress. We consider fully exposed fluid for only half surface interfaces fluid. thwarted in ...

growth-inducing exercise in hamsters were studied by examining (a) dependence of this phenomenon on a specific activity device, (b) its species-specificity, and (c) features of the running pattern which produce optimal growth acceleration. Acceleration of growth by exercise occurs in hamsters running on either horizontal discs or in vertical wheels, and in gerbils running in rotating wheels, an...

Observations of the Galactic Centre show evidence of disc-like structures of very young stars orbiting the central super-massive black hole within a distance of a few 0.1 pc. While it is widely accepted that about half of the stars form a relatively flat disc rotating clockwise on the sky, there is a substantial ongoing debate on whether there is a second, counter-clockwise disc of stars. By me...

Computers have added many new possibilities to the tool box used for visualizing science in general and relativity in particular. We present some new results from our own work: (2 + 1) dimensional Minkowski diagrams showing two spatial dimensions, extended wormhole visualization, and the illustration of accretion discs by using the approximation via a rigidly rotating disc of dust. We also disc...

We introduce a billiard scattering model consisting of two non-overlapping rotating discs in the context of the formation and structural properties of planetary rings. We show that due to the arrangement of the symmetric periodic orbits, stable orbits are found which in the configuration space lead to the appearance of patterns qualitatively similar to planetary rings. Rings associated with dif...