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Xerrada sobre "PIV appliations in vortex rings and oscillatory boundary layers"
24/09/2013 10:00
24/09/2013 11:00
Seminari del Departament Física. Subterrani Edifici P-II
Grup de Física Ambiental

La Doctora en Enginyeria Civil Anna Mujal Colilles farà una xerrada sobre PIV appliations in vortex rings and oscillatory boundary layers


PIV experiments were performed at a U-shape water oscillatory tunnel to study the roughness effects on the coherent structures formed at the bed. Previous researchers, both numerical and experimental, have defined several coherent structures within smooth and rough walls. However, and particularly, none of the experimental works have developed PIV experiments to study the formation and evolution of these features. Three different roughness walls (smooth and two roughness) and four wave Reynolds numbers were tested in order to compare the generation, evolution and final dissipation of oscillatory boundary layer coherent structures. Results show how oscillatory flows over smooth wall beds form vortex tubes for flows with a Reynolds number beyond 10^4. Rough wall flows show other type of structures such as single vortices shed from the wall, turbulent spots and finally shear layers. Vortices and turbulent spots were found for the same experiments, performed for the small roughness wall, whereas shear layers were only detected for large roughness wall experiments. Finally a POD analysis was performed in order to study the scales of such signatures.