As a daily life experience, when stirring cup of tea or coffee, one may observe vortices induced by the starting and stopping motion spoon. This paper investigated annular unsteady disk in water from experimental measurements numerical simulations. The circulation core radius are shown to scale with power laws diameter, stroke length, time agreement inviscid theoretical predictions.

Abstract This study investigates a re-entry scenario of an Apollo-like space capsule with Direct Numerical Simulations (DNS). The simulation includes the chemical equilibrium gas model. Cross-flow-like vortices are induced through random distributed roughness patches on surface. Two different machine learning methods used to predict maximum vorticity magnitude downstream pseudo-random patch, wa...

J. Soria Department of Mechanical Engineering, Monash University, Clayton, Australia • Results are presented on (1) the shear layer vortices developing in the free shear layers located between the separation point and the first shed Strouhal vortex of a circular cylinder and (2) the longitudinal vortices developing in the braid region of the Strouhal vortices in the wake. Evidence based on flow...

The problematic consequences regarding formation of air-core vortices at the intakes and drastic necessity a thorough investigation into phenomenon has resulted in particular attention being placed on Computational Fluid Dynamics (CFD) as an economically viable method. Two main approaches could be taken using CFD, namely Eulerian Lagrangian methods each which is characterized by specific advant...

A large jet encircling the inner core and carrying a significant part of the core angular momentum and axial vortices of ∼ 700 km diameter mainly clustering around the cylinder tangent to the solid inner core, are inferred from geomagnetic secular variation. These results are presented in the form of maps of axial vorticity in an equatorial section. The study takes advantage of the high precisi...

In this paper, we analyse by numerical simulations the nonlinear dynamics of the elliptic instability in the configurations of a single strained vortex and a system of two counter-rotating vortices. We show that although a weakly nonlinear regime associated with a limit cycle is possible, the nonlinear evolution far from the instability threshold is, in general, much more catastrophic for the v...

Essential structural properties of the non-trivial "string-wall-bounded" topological defects in hexagonal manganites are studied through homotopy group theory and spherical aberration-corrected scanning transmission electron microscopy. The appearance of a "string-wall-bounded" configuration in RMnO3 is shown to be strongly linked with the transformation of the degeneracy space. The defect core...

In the 2-dimensional anisotropic classical Heisenberg model with XY-symmetry there are nonplanar vortices which exhibit a localized structure of the z-components of the spins around the vortex center. We study how thermal noise induces a transition of this structure from one polarization to the opposite one. We describe the vortex core by a discrete Hamiltonian and consider a stationary solutio...

We propose and study a novel way to produce a dc transport of vortices when applying an ac electrical current to a sample. Specifically, we study superconductors with a graduated random pinning density, which transports interacting vortices as a ratchet system. We show that a ratchet effect appears as a consequence of the long range interactions between the vortices. The pinned vortices create ...