The Environmental Fluids Dynamics Group Presents a Lecture

1. The Environmental Fluids Dynamics Group Presents a Lecture Lord Julian Hunt, FRS Emeritus Professor of Climate Modeling Department of Earth Sciences University College London Trinity College TU Delft Tuesday, Feb. 11, 2013 11 am -12 p.m. 258 Fitzpatrick Hall Turbulence Near Wake and Boundary Layer Interfaces – Modeling and Simulations Turbulence near wake and boundary layer interfaces -modelling and simulations (In collaboration with J.Westerweel, J.Eisma, G.Elsinga, M. Braza, T. Ishihara ) Recent laboratory experiments, numerical simulations of high Reynolds number (R/lamda >10\3) are compared with approximate modelling of thin interface shear layers, with complex internal structure, that separate the turbulent region from the outer non-turbulent flow. Conditional analysis shows how at the outer edge a very thin layer with exponential decay of vorticity, on a scale equal to Kolmogorov micro scale, is adjacent to the layer with greater thickness lamda (Taylor micro scale) and algebraic variation of vorticity. The location of the layers have larger scale  fluctuations which penetrate into the turbulent region thin layer of thickness depending on the structure of the large scale turbulence, which explains the significant difference in mixing near the interface between wakes and turbulent boundary layers . The latter also develop one or more internal layers with similar scaling and jump conditions that lie between the interface and the wall layer. Current research is focused on the interface structure of the wall layer and general computational methods ( following Braza and Spalart) that include these interfacial layers .