Vortex definition and “vortex criteria”

Modelling vortex-vortex and vortex-boundary interaction

The motion of two-dimensional inviscid, incompressible fluid with regions of constant vorticity is studied for three classes of geophysically motivated problem. First, equilibria consisting of point vortices located near a vorticity interface generated by a shear flow are found analytically in the linear (small-amplitude) limit and then numerically for the fully nonlinear problem. The equilibri...

An objective definition of a vortex

The most widely used definitions of a vortex are not objective: they identify different structures as vortices in frames that rotate relative to each other. Yet a frame-independent vortex definition is essential for rotating flows and for flows with interacting vortices. Here we define a vortex as a set of fluid trajectories along which the strain acceleration tensor is indefinite over directio...

Kinematics of local vortex identification criteria

Vortex waistlines and vortex gas

A large body of work over the last few years [1] supports the picture of long thick vortices as the most important long range degrees of freedom for confinement. In this note we wish to examine more closely the manner in which a linear potential arises from vortex fluctuations. One customarily assumes a picture of randomly distributed vortices of certain thickness and basically arbitrary length...

An Aircraft Vortex Spacing System (AVOSS) For Dynamical Wake Vortex Spacing Criteria

A concept is presented for the development and implementation of a prototype Aircraft Vortex Spacing System (AVOSS). The purpose of the AVOSS is to use current and short-term predictions of the atmospheric state in approach and departure corridors to provide, to ATC facilities, dynamical weather dependent separation criteria with adequate stability and lead time for use in establishing arrival ...