IMA Postdoc Seminar (October 20, 2009)

Speaker: Ortiz-Duenas, Cecilia (IMA)

Title: Identifying, Characterizing and Modeling Coherent Structures of Turbulent Boundary layers

Abstract: Coherent structures, i.e. hairpin vortices, which align in groups or packets, were proposed as a fundamental structure of turbulent boundary layers more than 50 years ago in the literature. Although the existence of these structures and packets has been demonstrated, their generation, development, and interaction is not yet understood. Recently, planar and volumetric velocity measurements obtained by PIV provide direct information on spatial velocity variations as well as time-averaged statistics from which the characteristics of individual and of statistical ensembles of structures can be obtained. It is proposed here to integrate these experimental results into numerical models, such as the attached eddy model as described by Perry and Marusic (1995), to further the understanding of these structures under various conditions. The challenges in identifying, characterizing and modeling these coherent structures will be discussed.