Large-Eddy Simulation in Hydraulics

Complex turbulence phenomena are of great practical importance in hydraulics, including environmental flows, and require advanced methods for their successful computation. The Large Eddy Simulation (LES), in which the larger-scale turbulent motion is directly resolved and only the small-scale motion is modelled, is particularly suited for complex situations with dominant large-scale structures and unsteadiness. Due to the increasing computer power, LES is generally used more and more in Computational Fluid Dynamics. Also in hydraulics, it offers great potential, especially for near-field problems dominated by large-scale turbulence structures, and can be seen as the method of the future for such problems. This book gives an introduction to the LES method specially geared for hydraulic and environmental engineers. Compared with existing books on LES, it is less theoretically- and mathematically-demanding and, hence, it is easier to follow. It covers special features of flows in water bodies and summarizes the experience gained with LES for calculating such flows.

After introducing the basic concept of LES, the various subcomponents of the method are described, such as sub-grid-scale models for the small-scale motion, numerical methods for solving the governing equations, ILES as a special variant that uses numerical dissipation instead of an explicit sub-grid-scale model, treatment of boundary conditions, Hybrid LES-RANS methods necessary for high Reynolds number flows and finally methods for educing and visualizing the resolved eddies. In an extensive applications chapter, LES calculations are presented for a wide variety of hydraulic flows.

The book was written primarily as an introduction to LES for hydraulic and environmental engineers, but it will also be very useful as an entry to the subject of LES for researchers and students in all fields of fluids engineering. The applications part will further be useful to researchers interested in the physics of flows governed by the dynamics of coherent structures.

Wolfgang Rodi studied Aeronautical Engineering at the University of Stuttgart and received his Ph.D. degree in Mechanical Engineering from Imperial College, London, where he played a major role in the development of turbulence models that are now widely used in practice. In 1973 he moved to Karlsruhe University where he has been a Professor in Civil Engineering from 1981 until 2007, when he retired from this position. At Karlsruhe he pioneered the application of turbulence models in hydraulics but was also active in their extensive testing in other areas of engineering. In the 1990’s he shifted his interest to large eddy simulations of complex flows including those in hydraulics. He also supervised experiments that resulted in widely used benchmark test cases for calculation methods. Prof. Rodi published more than 100 journal papers and several monographs on turbulence modelling. He is an Associate Editor of the ASCE Journal of Hydraulic Engineering and an Editor of the Journal of Flow, Turbulence and Combustion. He has won several prestigious awards including the IAHR Ippen Award, the ASCE Hunter Rouse Hydraulic Engineering Lecture Award and the ASME Fluids Engineering Award. Since 2011 he is Distinguished Adjunct Professor at King Abdulaziz University, Jeddah, Saudi Arabia.

George Constantinescu obtained his first degree from the Civil Engineering Institute in Bucharest, Romania and his Ph.D. in Hydraulics from the University of Iowa, USA, in 1997. For the next 5 years he held post-doctoral positions with the Arizona State University and the Center for Turbulence Research, Stanford University. In 2004, he joined the Department of Civil and Environmental Engineering at the University of Iowa as an Assistant Professor and is currently an Associate Professor at the same university. Prof. Constantinescu has expertise in numerical simulations of complex turbulent flows using a wide range of modelling techniques and large-scale parallel computing. His present main research interests are in river restoration and modelling of stratified flows, shallow flows, flow and transport processes around hydraulic structures, sediment transport and morphodynamics in alluvial channels, flows in porous media. Prof Constantinescu is an Associate Editor of the ASCE Journal of Hydraulic Engineering and of the IAHR Journal of Hydraulic Research and the chairman of the IAHR Fluid Mechanics Committee. He co-authored 55 journal papers in the area of environmental fluid mechanics and hydraulics. He received two ASCE EWRI awards for Best Technical Note (2001) and in 2011 the Karl Emil Hilgard Hydraulic Prize for Best Paper in the ASCE Journal of Hydraulic Engineering.

Thorsten Stoesser studied Civil Engineering at the University of Karlsruhe and obtained his Ph.D. in this field from the University of Bristol in 2001. In 2006, after 5 years of post-doctoral research at the Institute of Hydromechanics at the University of Karlsruhe, he took up an Assistant Professorship at the Georgia Institute of Technology, Atlanta, USA, where he got promoted to Associate Professor shortly before he moved in May 2012 to take up his current position as Professor in the Hydro-environmental Research Centre at Cardiff University, UK. His expertise includes turbulence modelling via large eddy simulation (LES), rough-bed and vegetation hydrodynamics and advancing computational methods to study numerically fluid structure interaction. Prof. Stoesser has published 26 journal papers and two book chapters on developing, testing and applying Computational Fluid Dynamics methods to investigate hydrodynamics and turbulence in open-channel flow and has recently delivered keynote lectures on the subject at workshops and conferences. He is an Associate Editor of the IAHR Journal of Hydraulic Research. In 2012 he received the ASCE Karl Emil Hilgard Hydraulic Prize for his paper on "LES of flow through vegetation".