Symmetry (physics)

About: Symmetry (physics) is a research topic. Over the lifetime, 26435 publications have been published within this topic receiving 500189 citations. The topic is also known as: symmetry (physics) & physical symmetry.

The Theory of Axisymmetric Turbulence

Abstract: This paper discusses a type of turbulence in a uniform stream which is next to isotropic turbulence in order of simplicity. Instead of spherical symmetry, or isotropy, axially symmetical turbulence possesses symmetry about an axis which in practice is usually the direction of mean flow. The analysis is developed with the aid of invariant theory, as suggested by a previous paper by Robertson. The form of the fundamental velocity correlation is obtained, and scales of axisymmetric turbulence are defined. The results of greatest practical interest concern the time rates of change of the mean squares of the lateral and longitudinal velocity components. The rates of change involve two terms, the first representing viscous dissipation, and the second representing a transfer of energy from one component to the other due to the finite correlation between the velocity and pressure at neighbouring points. The effect of the velocity-pressure correlation is to bring the two velocity components towards equality, while the effect of the viscous dissipation will only be towards equality if an inequality between the curvatures at the origin of two particular velocity correlation coefficient curves, both of which are measurable, is obeyed. The rates of change of the mean squares of the vorticity components are also obtained.

Generalization of Dirac’s monopole to SU2 gauge fields

Abstract: Dirac’s monopole is generalized to SU2 gauge fields in five‐dimensional flat space or four‐dimensional spherical space. The generalized fields have SO5 symmetry. The method used is related to the concept of orthogonal gauge fields which is developed in an appendix. The angular momenta operators for the SO5 symmetrical fields are given.

Bifurcations and symmetry breaking in the wake of axisymmetric bodies

Abstract: We consider the generic problem of wake instabilities past fixed axisymmetric bodies, and focus on the extreme cases of a sphere and a flat disk. Numerical results reveal that the wakes of these two bodies evolve differently as the Reynolds number is increased. Especially, two new vortex shedding modes are identified behind a disk. To interpret these results, we introduce a model based on the theory of mode interactions in presence of O(2) symmetry. This model, which was initially developed for the Taylor-Couette system, allows us to explain the structural differences observed in the evolution of the two types of wakes and to accurately predict the evolution of the lift force.

Nonlinear magnetization dynamics under circularly polarized field.

Abstract: Exact analytical results are presented for the nonlinear large motion of the magnetization vector in a body with uniaxial symmetry subject to a circularly polarized field. The absence of chaos, the existence of pure time-harmonic magnetization modes with no generation of higher-order harmonics, and the existence of quasiperiodic magnetization modes with spontaneous breaking of the rotational symmetry are proven. Application to ferromagnetic resonance and connection with the Stoner-Wohlfarth model are discussed.