Turbulent Flows

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It was a pleasure to read this important book. To understand andpredict the development of turbulent flows represents both acontinuing scientific challenge and also a serious practicalproblem in many different fields.Professor Pope has based his book on graduate level lecturecourses on turbulence that he has presented at MIT and atCornell University. It is intended for students in engineering, applied mathematics, oceanography and atmospheric sciences, aswell as researchers and practising engineers. The emphasis is onturbulent flows, rather than on the theory of homogeneousturbulence, and only constant-density, nonreacting flows areconsidered. The author states that his aim is to explainconcepts and develop the necessary mathematical tools, ratherthan to provide a practical guide to turbulence modelling. The text is divided into two parts. Part I provides an introductionto turbulent flows and the fundamental physical processesinvolved. Topics discussed in separate chapters include: theequations of fluid motion, the statistical description ofturbulent flows, the mean flow equations, free shear flows,scales of turbulent motion and wall flows. The chapter on statistical methods for turbulence is particularly good; togetherwith the related appendices it represents a valuable andaccessible introduction to the subject. Several approaches formodelling or simulating turbulent flows are then described in Part II, in which the various chapters describe direct numericalsimulation (DNS), turbulent viscosity models such as the k-εmodel, Reynolds stress and related second-moment models,probability density function (pdf) models and large-eddysimulation (LES) techniques. Finally, some necessarymathematical tools are summarized in ten Appendices dealing witha wide range of relevant topics including tensors, Dirac delta functions, Fourier transforms, random processes, derivation ofpdf equations, characteristic functions and stochasticdescriptions of diffusion processes.I particularly enjoyed the chapters on modelling and simulationof turbulent flows. A unified treatment of the different typesof model has enabled the author to make valuable connectionsbetween them and to reach clear and logical conclusions about thestrengths and weaknesses of each approach. Over many yearsProfessor Pope has made very important contributions to thedevelopment and application of pdf methods for the prediction ofnonreactive and also reactive turbulent flows. The chapter onthis subject is an exceptionally clear description of thesepowerful and often under-utilized simulation methods. The finalchapter, on LES, provides an excellent introduction, withvaluable and novel insights into both the promise and theproblems of this relatively new and rapidly developing approach.It should be compulsory reading for many LES practitioners.Each section of the book contains a number of exercises, whichtypically invite the reader either to derive an expression thatis quoted in the text or to generalize an analysis set out inthe text. These exercises are often divided into several stages,and contain appropriate instructions, so that a diligent studentwill find his or her way through them. An advantage of theextensive use of appendices and student exercises is thatanalytical clarity and physical understanding are not obscuredby unnecessary algebraic detail or by the need to review basicmathematical tools. The result is an exceptionally clear presentation, together with an often penetrating critique of bothclassical methods and recent developments in the theory andmodelling of turbulent flows. There is excellent cross-referencing between one section and another, and anextensive and up-to-date bibliography.I strongly recommend this book to advanced students of fluidmechanics, to their teachers and to all researchers, engineersand others with a professional interest in turbulent flows.K N C Bray