The two known exact solutions of Einstein’s field equations describing rotating objects of physical significance – a black hole and a rigidly rotating disk of dust – are discussed using a single mathematical framework related to Jacobi’s inversion problem. Both solutions can be represented in such a form that they differ in the choice of a complex parameter and a real solution of the axisymmetr...

A theoretical investigation into the vortex-speed selection within the rotating-disk boundary layer is conducted. Two methods are used which are different to previous investigations in the literature and enable analysis of a particular vortex speed with respect to the rotating surface. Using these methods (together with arguments based on critical Reynolds numbers, unstable parameter ranges and...

Previous studies demonstrated an aftereffect of walking on a rotating treadmill, involving inadvertent circular navigation with eyes closed [podokinetic after-rotation (PKAR)]. We compared PKAR following unilateral and bilateral podokinetic (PK) stimulation to determine whether the left and right legs could be independently adapted. Each subject performed two sessions of PK stimulation, steppin...

We analyze the geometry of a rotating disk with a tangential acceleration in the framework of the Special Theory of Relativity, using the kinematic linear differential system that verifies the relative position vector of time-like curves in a Fermi reference. A numerical integration of these equations for a generic initial value problem is made up and the results are compared with those obtaine...