Integral Wall-Model for Large Eddy Simulations and Analytical Roughness Models for Turbulent Flows
Thursday, February 16, 2017
12:00 pm - 1:00 pm
Bryan Research 103
Charles Meneveau, Ph.D., Professor of Mechnical Engineering, Johns Hopkins University
We summarize a new wall model for LES, the integral wall model (iWMLES) and apply it to simulations of flow behavior within the roughness layer of turbulent boundary layer flow over rough surfaces. We consider several configurations consisting of arrays of rectangular-prism roughness elements with various spacings, aspect ratios and height distributions.The results provide clear evidence for exponential behavior of the mean flow with respect to the wall normal distance. Once established, the generic velocity profile shape is used to formulate a fully analytical model for the effective drag exerted by turbulent flow on a surface covered with arrays of rectangular-prism roughness elements. The approach is based on the integral method by von-Karman Pohlhausen in which a shape function is assumed for the mean velocity profile and its parameters are determined based on momentum conservation and fundamental constraints. Comparisons between model predictions and experimental/numerical data from the existing literature as well as LES data from this study are presented.Charles Meneveau is the Louis M. Sardella Professor in the Department of Mechanical Engineering at Johns Hopkins University. He also has a joint appointment in the Geography and Environmental Engineering Department and is Associate Director of the Institute for Data Intensive Engineering and Science (IDIES) at Johns Hopkins.