Fecha: Miércoles, 15 de febrero de 2012
Lugar: Edificio CEAMA, Sala de Conferencias, 2ª planta
Horario: 12:00 horas
Descripción: Seminario impartido por el Profesor Jonathan F. Morrison, del Imperial College de Londres
Resumen: The streamwise velocity component in fully developed turbulent channel flow is studied for two very rough surfaces and a smooth surface at comparable Reynolds numbers. One rough surface comprises sparse and isotropic grit with a highly non- Gaussian distribution. The other is a uniform mesh consisting of twisted rectangular elements which form a diamond pattern. The flow is shown to be two-dimensional and fully developed up to the fourth-order moment of velocity. The mean velocity profile over the grit surface exhibits self-similarity (in the form of a logarithmic law) within the limited range of 0.04 < y/h < 0.06, but the profile over the mesh surface does not, even though the mean velocity deficit and higher moments (up to the fourth order) all exhibit outer scaling over both surfaces. The distinction between self-similarity and outer similarity is clarified and the importance of the former is explained. Surprisingly, the energy balance within the supposed log region on the grit surface does not conform to the local-equilibrium approximation. The wake strength is shown to increase slightly over the grit surface but decrease over the mesh surface. The latter result is contrary to recent measurements in rough-wall boundary layers. Single- and two-point velocity correlations reveal the presence of large-scale streamwise structures with circulation in the plane orthogonal to the mean velocity.
Organiza: Máster Oficial Interuniversitario Hidráulica Ambiental
Más información: http://masteres.ugr.es/hidraulicaambiental/
Información de contacto: Miguel Ortega, Instituto Interuniversitario de Investigación Sistema Tierra
http://www.ugr.es/~miguelos/
Grupo de Dinámica de Flujos Ambientales
CEAMA-Avda del Mediterráneo s/n
18071 Granada
Tf: 958 241000 ext. 31200
Fax: 958 132479
gpyc@ugr.es