Rainer Friedrich

Wolfgang Rodi

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.

Proceedings of the Euromech Colloquium 412, held in Munich, Germany 4∓6 October 2000

Advances in LES of Complex Flows

Bernard Geurts

Olivier Métais

This volume contains the proceedings of the 2001 DLES4 workshop. It describes and discusses state-of-the-art modeling and simulation approaches for complex flows. Fundamental turbulence and modeling issues but also elements from modern numerical analysis are at the heart of this field of interest.

Direct and Large-Eddy Simulation IV

Stefan Reis

The occurrence of high concentrations of ozone during summer episodes in the troposphere over Europe is a problem still unsolved. Although a number· of measures have been implemented that will achieve a further reduction of precursor emissions in the next years, this will not be sufficient to reduce the ozone concentration to levels below thresholds set up to protect human health and plants. Thus, further reductions of emissions of volatile organic compounds and nitrogen oxides are necessary. However, with regard to the increasing costs associated with increasing emission reduction, it is essential to implement abatement strategies, that are effective, i.e. achieving the environmental aim set up, and efficient, i. e. doing this with the least costs possible. In this book, the authors describe the features and the application of a methodology and a model system to identify effective and efficient strategies to reduce ambient concentrations of tropospheric ozone to comply with thresholds set up to protect human health, agricultural crops and ecosystems. Furthermore, macroeconomic impacts of such strategies are addressed and, as burden and benefits of these strategies are not equally distributed between countries, different burden sharing schemes are discussed. The content of this book is based on results of a comprehensive research project, the project INFOS (assessment of policy instruments for efficient ozone abatement strategies in Europe), funded by the European Commission (Directorate General XII) under the Fourth Framework Programme for research, technological development and demonstration activities.

Developing Efficient Strategies for the Reduction of Ozone Precursor Emissions in Europe

Tropospheric Ozone Abatement

The fifth ERCOFfAC workshop 'Direct and Large-Eddy Simulation-5' (DLES-5) was held at the Munich University of Technology, August 27-29, 2003. It is part of a series of workshops that originated at the University of Surrey in 1994 with the intention to provide a forum for presentation and dis cussion of recent developments in the field of direct and large-eddy simula tion. Over the years the DLES-series has grown into a major international venue focussed on all aspects of DNS and LES, but also on hybrid methods like RANSILES coupling and detached-eddy simulation designed to provide reliable answers to technical flow problems at reasonable computational cost. DLES-5 was attended by 111 delegates from 15 countries. Its three-day pro gramme covered ten invited lectures and 63 original contributions partially pre sented in parallel sessions. The workshop was financially supported by the fol lowing companies, institutions and organizations: ANSYS Germany GmbH, AUDI AG, BMW Group, ERCOFfAC, FORTVER (Bavarian Research Asso ciation on Combustion), JM BURGERS CENTRE for Fluid Dynamics. Their help is gratefully acknowledged. The present Proceedings contain the written versions of nine invited lectures and fifty-nine selected and reviewed contributions which are organized in four parts: 1 Issues in LES modelling and numerics 2 Laminar-turbulent transition 3 Turbulent flows involving complex physical phenomena 4 Turbulent flows in complex geometries and in technical applications.

Proceedings of the fifth international ERCOFTAC Workshop on direct and large-eddy simulation held at the Munich University of Technology, August 27–29, 2003

Direct and Large-Eddy Simulation V

"Milman Parry's comparative study of Homer and Southslavic oral song had demonstrated the existence of an oral tradition behind and within the Homeric Epic, thus establishing an indisputable link between Homer and oral poetry. Yet its exact nature has remained a moot point. For equally indisputable is the fact of the coexistence of oral and literate features within the Homeric Epic. Thus not behaving as either a straight oral song or as a straight literate text tout court, the Homeric Epic calls into question the prevailing Parryist axiom of the oral Homer. The link between Homer and oral poetry has thus become an open question again: it is, in fact, the New Homeric Question that turns on the roles of orality and literacy in the genesis of the Homeric Epic.To clarify it this book experiments with a third term: postorality. As a postoral poet, having initially been trained as an oral bard absorbing the Hellenic oral tradition, Homer would have acquired literacy in the course of his career as an oral singer. It enabled him to widen, deepen, and refine his epic art, thereby giving rise to an epic as complex and unique, in terms of structure, characterization, and intellectual substance, as the Iliad."--

Orality and Literacy in the Homeric Epic

Postoral Homer

The principle of formular economy is to protect an oral poet's thesaurus of formulas against overload through the avoidance of metrical doublets. Being specific to oral poetry, it serves as the chief criterion for determining the orality of a text (known as the `economy test of orality'). Parryism's Theory of the Oral Homer is predicated on the assumption of the poet's strict observance of this principle. This study, examining the hitherto untested Parryist assumption, reveals a high frequency of breaches of economy in Homer, and demonstrates that these are for the most part motivated by poetic considerations. It arrives at the conclusion that formular economy and the resulting schematized diction are residual in the Homeric epics where they yield to a largely schema-free style of composition.

Rainer Friedrich

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