scholarly journals Differential and Variational Formalism for an Acoustically Levitating Drop

2016 ◽  
Vol 220 (3) ◽  
pp. 359-375
Author(s):  
M. O. Chernova ◽  
I. A. Lukovsky ◽  
A. N. Timokha
Author(s):  
F. P. POULIS ◽  
J. M. SALIM

Motivated by an axiomatic approach to characterize space-time it is investigated a reformulation of Einstein's gravity where the pseudo-riemannian geometry is substituted by a Weyl one. It is presented the main properties of the Weyl geometry and it is shown that it gives extra contributions to the trajectories of test particles, serving as one more motivation to study general relativity in Weyl geometry. It is introduced its variational formalism and it is established the coupling with other physical fields in such a way that the theory acquires a gauge symmetry for the geometrical fields. It is shown that this symmetry is still present for the red-shift and it is concluded that for cosmological models it opens the possibility that observations can be fully described by the new geometrical scalar field. It is concluded then that this reformulation, although representing a theoretical advance, still needs a complete description of their objects.


2014 ◽  
Vol 71 (6) ◽  
pp. 2104-2113 ◽  
Author(s):  
Yoshi K. Sasaki

Abstract The entropic balance theory has been applied with outstanding results to explain many important aspects of tornadic phenomena. The theory was originally developed in variational (probabilistic) field Lagrangian formalism, or in short, variational formalism, with Lagrangian density and action appropriate for supercell-storm and tornadic phenomena. The variational formalism is broadly used in in modern physics, not only in classical mechanics, with Lagrangian density and action designed for each physical problem properly. The Clebsch transformation (equation) was derived in the classical variational formalism but has not been used because of the unobservable and nonmeteorological Lagrange multiplier. The entropic balance condition is thus developed from the Clebsch transformation, changing the unobservable nonmeteorological Lagrange multiplier to observable meteorological rotational flow velocity with entropy and making it applicable to tornadic phenomena. Theoretical details of the entropic balance are presented such as the entropic right-hand rule, entropic dipole, source and sink, overshooting mechanism of hydrometeors against westerlies and the existence of single and multiple vortices and their relation to tornadogenesis. These results are in reasonable agreement with the many observations and data analysis publications. The Clebsch transformation and entropic balance are the new balance conditions, different from the known other balance conditions such as hydrostatic, (quasi-)geostrophic, cyclostrophic, Boussinesq, and anelastic balance. The variations in calculus of variations and in the classical variational formalism are hypothetical. However, this article suggests that the hypothetical variations could be physical, relating to quantum variations and their interaction with the classical systems.


2011 ◽  
Vol 03 ◽  
pp. 254-265 ◽  
Author(s):  
G. OLIVEIRA-NETO ◽  
G. A. MONERAT ◽  
E. V. CORRÊA SILVA ◽  
C. NEVES ◽  
L. G. FERREIRA FILHO

In the present work, we study the quantum cosmology description of a Friedmann-Robertson-Walker model in the presence of a stiff matter perfect fluid and a negative cosmological constant. We work in the Schutz's variational formalism and the spatial sections have constant negative curvature. We quantize the model and obtain the appropriate Wheeler-DeWitt equation. In this model the states are bounded therefore we compute the discrete energy spectrum and the corresponding eigenfunctions. In the present work, we consider only the negative eigenvalues and their corresponding eigenfunctions. This choice implies that the energy density of the perfect fluid is negative. A stiff matter perfect fluid with this property produces a model with a bouncing solution, at the classical level, free from an initial singularity. After that, we use the eigenfunctions in order to construct wave packets and evaluate the time-dependent expectation value of the scale factor. We find that it oscillates between maximum and minimum values. Since the expectation value of the scale factor never vanishes, we confirm that this model is free from an initial singularity, also, at the quantum level.


2006 ◽  
Vol 49 (5) ◽  
pp. 531-536
Author(s):  
O. V. Baburova ◽  
V. F. Korolev ◽  
I. Ya. Umyarova

Author(s):  
Asher Yahalom

In previous papers [1–4] we have described how by minimizing the fluid action numerically one can obtain a solution of the fluid steady state equations. The action which was used was the four function action of Seliger & Whitham [5]. In a recent paper [6] we describe how one can improve upon previous art by reducing the number of variables in the action. Three independent functions variational formalism for stationary and non-stationary barotropic flows is introduced. This is less than the four variables which appear in the standard equations of fluid dynamics which are the velocity field ν⃗ and the density ρ. In this paper we will discuss a possible finite element approach related to the usage of the new action principles as basis for a CFD algorithms.


2019 ◽  
Vol 28 (06) ◽  
pp. 1950078
Author(s):  
Bob Osano ◽  
Timothy Oreta

The interaction of dark energy and dark matter has been studied widely using various formalisms in an effort to understand the physics of such gravitational interactions. Such studies are motivated by the idea that they might hold the key to resolving some of the outstanding problems in cosmology. We will consider the relativistic convective variational formalism in our study of dark matter (hereafter DM)-dark energy (hereafter DE) interaction. In particular, we go beyond the gravitational interaction and consider the potential entrainment phenomena involving the two dark-sector constituents. Ours is a formalism paper and focuses on the theoretical considerations that inform the modeling of such interactions.


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