503,051 research outputs found
Effective viscosity of grease ice in linearized gravity waves
Grease ice is an agglomeration of disc-shaped ice crystals, named frazil ice,
which forms in turbulent waters of the Polar Oceans and in rivers as well. It
has been recognized that the properties of grease ice to damp surface gravity
waves could be explained in terms of the effective viscosity of the ice slurry.
This paper is devoted to the study of the dynamics of a suspension of
disc-shaped particles in a gravity wave field. For dilute suspensions,
depending on the strength and frequency of the external wave flow, two
orientation regimes of the particles are predicted: a preferential orientation
regime with the particles rotating in coherent fashion with the wave field, and
a random orientation regime in which the particles oscillate around their
initial orientation while diffusing under the effect of Brownian motion. For
both motion regimes, the effective viscosity has been derived as a function of
the wave frequency, wave amplitude and aspect ratio of the particles. Model
predictions have been compared with wave attenuation data in frazil ice layers
grown in wave tanks.Comment: 13 pages, 3 eps figures included; one more section on inertia effect
The theory of the double preparation: discerned and indiscerned particles
In this paper we propose a deterministic and realistic quantum mechanics
interpretation which may correspond to Louis de Broglie's "double solution
theory". Louis de Broglie considers two solutions to the Schr\"odinger
equation, a singular and physical wave u representing the particle (soliton
wave) and a regular wave representing probability (statistical wave). We return
to the idea of two solutions, but in the form of an interpretation of the wave
function based on two different preparations of the quantum system. We
demonstrate the necessity of this double interpretation when the particles are
subjected to a semi-classical field by studying the convergence of the
Schr\"odinger equation when the Planck constant tends to 0. For this
convergence, we reexamine not only the foundations of quantum mechanics but
also those of classical mechanics, and in particular two important paradox of
classical mechanics: the interpretation of the principle of least action and
the the Gibbs paradox. We find two very different convergences which depend on
the preparation of the quantum particles: particles called indiscerned
(prepared in the same way and whose initial density is regular, such as atomic
beams) and particles called discerned (whose density is singular, such as
coherent states). These results are based on the Minplus analysis, a new branch
of mathematics that we have developed following Maslov, and on the Minplus path
integral which is the analog in classical mechanics of the Feynman path
integral in quantum mechanics. The indiscerned (or discerned) quantum particles
converge to indiscerned (or discerned) classical particles and we deduce that
the de Broglie-Bohm pilot wave is the correct interpretation for the
indiscerned quantum particles (wave statistics) and the Schr\"odinger
interpretation is the correct interpretation for discerned quantum particles
(wave soliton). Finally, we show that this double interpretation can be
extended to the non semi-classical case.Comment: 11 pages, 5 figure
Determining particle density using known material Hugeniot curves
A method is detailed to determine the density of particles wherein the closing velocity is known between the impacting particles and a plate of known material. Either the shock wave velocity or the material velocity produced in the plate upon impact by an unknown material particle is determined and compared with the corresponding shock wave or material velocity that would by produced by different known material particles having the same closing velocity upon impact with the plate. The unknown material particle density is derived by obtaining a coincidence of the shock wave velocity or material velocity conditions initially produced upon impact between the known material plate and one of the different material particles and from the fact that shock wave velocity and material velocity are ordered on the impacting particle material density alone
Replacing the Singlet Spinor of the EPR-B Experiment in the Configuration Space with two Single-Particle Spinors in Physical Space
Recently, for spinless non-relativistic particles, Norsen, Marian and Oriols
show that in the de Broglie-Bohm interpretation it is possible to replace the
wave function in the configuration space by single-particle wave functions in
physical space. In this paper, we show that this replacment of the wave
function in the configuration space by single-particle functions in the
3D-space is also possible for particles with spin, in particular for the
particles of the EPR-B experiment, the Bohm version of the
Einstein-Podolsky-Rosen experiment.Comment: 17 pages, 5 figures, accepted in Foundations of Physics 201
Phase transition in the collisionless regime for wave-particle interaction
Gibbs statistical mechanics is derived for the Hamiltonian system coupling
self-consistently a wave to N particles. This identifies Landau damping with a
regime where a second order phase transition occurs. For nonequilibrium initial
data with warm particles, a critical initial wave intensity is found: above it,
thermodynamics predicts a finite wave amplitude in the limit of infinite N;
below it, the equilibrium amplitude vanishes. Simulations support these
predictions providing new insight on the long-time nonlinear fate of the wave
due to Landau damping in plasmas.Comment: 12 pages (RevTeX), 2 figures (PostScript
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