We conduct long-time simulations with a Hamiltonian particle-mesh method for ideal fluid flow, to determine the statistical mean vorticity field of the discretization. Lagrangian and Eulerian statistical models are proposed for the discrete dynamics, and these are compared against numerical experiments. The observed results are in excellent agreement with the theoretical models, as well as with...

Simple, e cient and accurate nite di erence methods are introduced for 3D unsteady viscous incompressible ows in the vorticity-vector potential formulation on non-staggered grids. Two di erent types of methods are discussed. They di er in the implementation of the normal component of the vorticity boundary condition and consequently the enforcement of the divergence free condition for vorticity...

The linear wave and baroclinic instability properties of various geostrophic models valid when the Rossby number is small are investigated. The models are the ‘‘L1’’ dynamics, the ‘‘geostrophic potential vorticity’’ equations, and the more familiar quasigeostrophic and planetary geostrophic equations. Multilayer shallow water equations are used as a control. The goal is to determine whether the...

This Rapid Communication sets forth the mechanism by which mesoscale staircase structures condense to form macroscopic states of enhanced confinement. Density, vorticity, and turbulent potential enstrophy are the variables for this model. Formation of the staircase structures is due to inhomogeneous mixing of (generalized) potential vorticity (PV). Such mixing results in the local sharpening of...

We dispose of some objections raised by Manko et al. [2] on a recently published paper on the role of Poynting vector in the ocurrence of vorticity in electrovaccum spacetimes [1]. In order to confirm the Bonnor’s hyphothesis about the role of the electromagnetic energy flux as the responsible for the vorticity in the surrounding of non–rotating sources of some gravitational fields [3], Herrera...