An anisotropic refinement criterion suitable for Finite-Volume methods is presented and Navier–Stokes solutions are reported for the lid-driven cavity flow configuration at Re 1⁄4 1000 with adaptive anisotropic meshes (h-refinement). The a posteriori error estimation criterion is based on the assessment of the goodness-of-fit of the least squares regression used to perform the variables profile...

We demonstrate the way in which vortex rings in neutral superfluids are equivalent to massive, charged, elastic strings in an electromagnetic field defined locally on the string from a Kalb-Ramond gauge field. We argue that the action thus obtained describes an intermediate scale of vortex motion with phonon fluctuations of the line between the incompressible hydrodynamic régime and the microsc...

The stretched-spiral vortex model is used to calculate the velocity-scalar cross spectrum for homogeneous, isotropic turbulence in the presence of a mean scalar gradient. The only nonzero component of the cospectrum is that contributed by the velocity component in the direction of the imposed scalar gradient while the quadrature spectrum is identically zero, in agreement with experiment. For th...

One-dimensional stability analysis of a hydraulic system composed of a penstock, a runner, and a draft tube was carried out to determine the cause of the full load draft tube surge. It is assumed that the cavity volume at the runner exit is a function of the pressure at the vortex core evaluated from the instantaneous local pressure at the runner exit and an additional pressure decrease due to ...

— Vortices can be produced and ingested into the intake of a jet engine during high power operation in the vicinity of solid surfaces causing Foreign Object Damage (FOD) or compressor stall and engine surge problems. This can occur when the engine is mounted on the wing of a plane during takeoff and engine ground runs or when the engine is placed inside a test cell for testing after an engine o...

The stretched-spiral vortex model is used to calculate the velocity-scalar cross spectrum for homogeneous, isotropic turbulence in the presence of a mean scalar gradient. The only nonzero component of the cospectrum is that contributed by the velocity component in the direction of the imposed scalar gradient while the quadrature spectrum is identically zero, in agreement with experiment. For th...

We investigate the pinning and driven dynamics of vortices interacting with twin boundaries using large scale molecular-dynamics simulations on samples with near one million pinning sites. For low applied driving forces, the vortex lattice orients itself parallel to the twin boundary and we observe the creation of a flux gradient and vortex-free region near the edges of the twin boundary. For i...

We observe interlaced square vortex lattices in rotating dilute-gas spinor Bose-Einstein condensates (BEC). After preparing a hexagonal vortex lattice in a one-component BEC in an internal atomic state |1, we coherently transfer a fraction of the superfluid to a different state |2. The subsequent evolution of this pseudo-spin-1/2 superfluid towards a state of offset square lattices involves an ...

Dust particles charging in a stratified positive column of a low-pressure DC glow discharge was investigated theoretically. The presented model consists of (i) previously developed 1D selfconsistent model for discharge parameters on the tube axis; (ii) ambipolar approximation for radial electric potential distribution and the assumption that the electron energy distribution function in radial d...

– We study the statistics of turbulent velocity fluctuations in the neighbourhood of a strong large scale vortex at very large Reynolds number. At each distance from the vortex core, we observe that the velocity spectrum has a power law " inertial range " of scales and that intermittency – defined as the variation of the probability density function (PDF) of velocity increments as the length of...