The influence of fluctuation fields on the force-free field .2. The local expansion

In Paper I (Hu, 1982), we discussed the the influence of fluctuation fields on the force-free field for the case of conventional turbulence and demonstrated the general relationships. In the present paper, by using the approach of local expansion, the equation of average force-free field is obtained as (1+b)×B 0=(#x002B;a)B 0#x002B;a (1)×B 0#x002B;K. The average coefficientsa,a (1),b, andK show the influence of the fluctuation fields in small scale on the configurations of magnetic field in large scale. As the average magnetic field is no longer parallel to the average electric current, the average configurations of force-free fields are more general and complex than the usual ones. From the view point of physics, the energy and momentum of the turbulent structures should have influence on the equilibrium of the average fields. Several examples are discussed, and they show the basic features of the fluctuation fields and the influence of fluctuation fields on the average configurations of magnetic fields. The astrophysical environments are often in the turbulent state, the results of the present paper may be applied to the turbulent plasma where the magnetic field is strong.

La Planificación Estratégica como instrumento de gestión pública en el gobierno local: Análisis de caso

[ES] Los responsables políticos y los gestores de los gobiernos locales de las ciudades se enfrentan con un problema recurrente: cómo atender, con recursos cada vez más escasos, las demandas de sus ciudadanos y a los actores con interés en su territorio, en términos tanto de eficacia en la prestación de servicios como de profundización democrática. Utilizando una metodología cualitativa, el objetivo de este trabajo es identificar hasta que punto un proceso de planificación estratégica pública sirve para compatibilizar las demandas de democracia y eficacia en el gobierno y administración pública local, involucrando a los ciudadanos y a los actores económicos privados. Este estudio de caso demuestra esa posibilidad aunque se hacen necesarias investigaciones comparativas adicionales.

Poniendo en valor el patrimonio físico y deportivo local

Duración (en horas): Más de 50 horas. Destinatario: Estudiante y Docente

Vortex dislocation in wake-type flow caused by local spanwise nonuniformity

DNS of spatiotemporal evolution of a wake-type flow is performed. In the incoming flow, a local spanwise nonuniformity in momentum defect is initially imposed. Results show that the spanwise nonuniformity leads to a series of symmetric twist vortex dislocation in downstream of the flow. Vortex line variations and substantial transition of vorticity from spanwise to the streamwise and vertical directions clearly feature the generation of a vortex dislocation and the real vortex linking in the dislocation. Dynamical process and the mechanism responsible for the vortex dislocation are described.