This collection of papers presents a broad range of topics in DNS and LES, from new developments in LES modeling to DNS and LES for supersonic and hypersonic boundary layers. The book provides an extensive view of the state of the art in the field.

The present book contains contributions presented at the Fourth Symposium on Hybrid RANS-LES Methods, held in Beijing, China, 28-30 September 2011, being a continuation of symposia taking place in Stockholm (Sweden, 2005), in Corfu (Greece, 2007), and Gdansk (Poland, 2009). The contributions to the last two symposia were published as NNFM, Vol. 97 and Vol. 111. At the Beijing symposium, along with seven invited keynotes, another 46 papers (plus 5 posters) were presented addressing topics on Novel turbulence-resolving simulation and modelling, Improved hybrid RANS-LES methods, Comparative studies of difference modelling methods, Modelling-related numerical issues and Industrial applications.. The present book reflects recent activities and new progress made in the development and applications of hybrid RANS-LES methods in general.

The articles focus on new developments in the field of large-eddy simulation of complex flows and are related to the topics: modelling and analysis of subgrid scales, numerical issues in LES cartesian grids for complex geometries, curvilinear and non-structured grids for complex geometries. DES and RANS-LES coupling, aircraft wake vortices, combustion and magnetohydrodynamics. Progress has been made not only in understanding and modelling the dynamics of unresolved scales, but also in designing means that prevent the contamination of LES predictions by discretization errors. Progress is reported as well on the use of cartesian and curvilinear coordinates to compute flow in and around complex geometries and in the field of LES with unstructured grids. A chapter is dedicated to the detached-eddy simulation technique and its recent achievements and to the promising technique of coupling RANS and LES solutions in order to push the resolution-based Reynolds number limit of wall-resolving LES to higher values. Complexity due to physical mechanisms links the last two chapters. It is shown that LES constitutes the tool to analyse the physics of aircraft wake vortices during landing and takeoff. Its thorough understanding is a prerequisite for reliable predictions of the distance between consecutive landing airplanes. Subgrid combustion modelling for LES of single and two-phase reacting flows is demonstrated to have the potential to deal with finite-rate kinetics in high Reynolds number flows of full-scale gas turbine engines. Fluctuating magnetic fields are more reliably predicted by LES when tensor-diffusivity rather than gradient-diffusion models are used. An encouraging result in the context of turbulence control by magnetic fields.

Turbulence modelling has long been, and will remain, one of the most important t- ics in turbulence research, challenging scientists and engineers in the academic world and in the industrial society. Over the past decade, Detached Eddy Simulation (DES) and other hybrid RANS-LES methods have received increasing attention from the turbulence-research community, as well as from industrial CFD engineers. Indeed, as an engineering modelling approach, hybrid RANS-LES methods have acquired a remarkable profile in modelling turbulent flows of industrial interest in relation to, for example, transportation, energy production and the environment. The advantage exploited with hybrid RANS-LES modelling approaches, being - tentially more computationally efficient than LES and more accurate than (unsteady) RANS, has motivated numerous research and development activities. These activities, together with industrial applications, have been further facilitated over the recent years by the rapid development of modern computing resources. As a European initiative, the EU project DESider (Detached Eddy Simulation for Industrial Aerodynamics, 2004-2007), has been one of the earliest and most systematic international R&D effort with its focus on development, improvement and applications of a variety of existing and new hybrid RANS-LES modelling approaches, as well as on related numerical issues. In association with the DESider project, two subsequent international symposia on hybrid RANS-LES methods have been arranged in Stockholm (Sweden, 2005) and in Corfu (Greece, 2007), respectively. The present book is a result of the Second Symposium on Hybrid RANS-LES Methods, held in Corfu, Greece, 17-18 June 2007.

This unique text provides engineering students and practicing professionals with a comprehensive set of practical, hands-on guidelines and dozens of step-by-step examples for performing state-of-the-art, reliable computational fluid dynamics (CFD) and turbulence modeling. Key CFD and turbulence programs are included as well. The text first reviews basic CFD theory, and then details advanced applied theories for estimating turbulence, including new algorithms created by the author. The book gives practical advice on selecting appropriate turbulence models and presents best CFD practices for modeling and generating reliable simulations. The author gathered and developed the book’s hundreds of tips, tricks, and examples over three decades of research and development at three national laboratories and at the University of New Mexico—many in print for the first time in this book. The book also places a strong emphasis on recent CFD and turbulence advancements found in the literature over the past five to 10 years. Readers can apply the author’s advice and insights whether using commercial or national laboratory software such as ANSYS Fluent, STAR-CCM, COMSOL, Flownex, SimScale, OpenFOAM, Fuego, KIVA, BIGHORN, or their own computational tools. Applied Computational Fluid Dynamics and Turbulence Modeling is a practical, complementary companion for academic CFD textbooks and senior project courses in mechanical, civil, chemical, and nuclear engineering; senior undergraduate and graduate CFD and turbulence modeling courses; and for professionals developing commercial and research applications.