Road Vehicle Aerodynamic Design: an Introduction. R.H. Barnard
New text books dealing with road vehicle aerodynamics have been scarce in recent years, in contrast to the level of interest in this field from both professional engineers and the armchair enthusiast. The publication of Dr Bamard's book was therefore a welcome addition and it has already earned a reputation as the introductory text on road vehicle aerodynamics.
Readers familiar with the informative but relaxed style of Aircraft Flight, Barnard and Phillpott's earlier publication, will feel immediately at home. The text addresses a subject area for which there are few mathematical explanations or models by explaining physical principles clearly and concisely with the aid of quality figures and sketches, together with numerous black and white photographs.
After introductory material which explains basic aerodynamic characteristics of bodies in ground effect and the implication of aerodynamic loads on vehicle handling and fuel economy, there are chapters dealing specifically with passenger cars, heavy goods vehicles, and sports/competition vehicles. In addition, the increasingly important areas of crosswind effects and internal air flows are concisely summarised. A brief but realistic assessment of the developing contribution to the understanding of these flowfields being offered by computational fluid dynamics is also included together with a summary of windtunnel test techniques both are areas which would justify a text themselves.
Road Vehicle Aerodynamics would appeal to a wide variety of readers with varying backgrounds. While being pitched primarily at undergraduate engineers and automotive designers it contains a host of useful references which facilitate and encourage further study. In an area of such active research it is perhaps inevitable that text books will have a limited shelf life but Dr Bamard's book addresses many fundamental principles in such a way as to ensure it will remain a useful text for many years.
Dr Kevin Garry, C Eng, MRAeS
From The Aeronautical Journal, Vol. 102, No. 1011, January 1998.
Road Vehicle Aerodynamic Design is a practical rather than theoretical guide to the techniques required to observe and to understand the behaviour of the air round and through a moving vehicle. It is not dedicated to race cars although author Richard Bamard's deep interest in racing is apparent from the number of times he uses racing cars as illustrations of the more important effects, and a whole chapter devoted to a qualitative assessment of the state of this art. Although he appears not to claim it explicitly, I inferred from the book that Bamard was involved in the aerodynamic design, testing and development of the successful Spice Group C cars of the 1980s. The book starts with definitions and explanations of many of the terms used in aerodynamics and sets the scene with many tables of typical values of lift and drag which will interest Race Tech readers. As ever with such performance data, the originators do not always provide the whole truth, so the reader has no option but to take them on trust, but they are still a useful addition to the public domain. An important warning appears early in the book to avoid applying free-flying aircraft information too slavishly to road vehicles - the flow regimes differ widely. An equally valuable message concludes the chapter on racing car aerodynamics - "it is no longer sufficient to use intuition alone to make aerodynamic improvements". The physics underlying the way that downforce can improve performance is covered in some detail, unfortunately repeating a common mistake by suggesting that friction coefficients cannot conventionally exceed 1. The efficiency of underbody-generated downforce is mentioned, but it would have been better for racing-oriented readers if it had been explored and explained more thoroughly. Internal air flows are well covered, and although a lot of attention is given to heating, ventilation and other comfort features mainly appropriate to passenger cars, the efficient provision of air flows for important race car components, including the driver, is discussed.
The publishers recommend this book to people working in, or aiming to work in, the road vehicle design industry. It's hard to identify a specific target readership in racing. Professional aerodynamicists working on cars will know the topic already. Race engineers will find it a useful refresher on a subject of crucial importance to them, perhaps even helping them to rationalise complex or puzzling observations. Designers seeking inspiration to cure an intractable problem may well be reminded of a solution used in the past to good effect. The compact inexpensive book has a wealth of empirical information from a wide variety of sources, together with sufficient unifying theory and explanation to make it useful to a wide range of people.
From Race Tech, June/July 1999
From Proceedings of the Institution of Mechanical Engineers
Vol 211, Part D, No. 5, 1997
ROAD VEHICLE AERODYNAMIC DESIGN
R H Barnard
Despite the prominence of aerodynamics in the overall design of road vehicles there is remarkably little information available through published texts. Any new and up-to-date addition is therefore very welcome and it was with great enthusiasm that I accepted this opportunity to review a new text from an author who is well known and respected in the field. The cover notes explain that the book is targeted at students, engineers and designers working in the engineering field using a largely non-mathematical approach. That immediately gave me some cause for concern since of those three groups the first two undoubtedly require a greater depth of understanding than does the third. After having read the book, that concern has been partially alleviated by a reasonably comprehensive use of references to support the text, but I am still left with the feeling that the compromises that have been made to meet the requirements of such a wide audience may leave some readers a little disappointed.
All of the major topics relating to vehicle aerodynamics are covered, from basic descriptions of the lift and drag forces that act on a moving vehicle to more specific internal and external considerations ranging from ventilation and cooling to cross-wind influences. More specific aerodynamic considerations are also discussed for the full spectrum of road vehicles including passenger cars, commercial vehicles and racing cars. In addition, the author provides an introduction to testing in the wind tunnel and on the road and he concludes with a chapter on the increasingly important topic of computational flow simulation and prediction.
The clarity of presentation that Barnard has achieved is to be applauded. The text is easy to read and the illustrations are plentiful, simple and clear. Non-technical readers will, I am sure, gain an enthusiasm for the subject while also gaining a modest understanding. Whether that ill also be true of engineers and students is less clear.
Initial 'tests' on my own undergraduate and postgraduate students revealed that the book was received enthusiastically and that it achieved that rare distinction for a text-book of being read cover to cover. However, that initial enthusiasm eventually developed into mild frustration and the book was soon returned to the book shelf to be replaced by the old, standard texts which provide substantially greater technical depth and insight.
In conclusion I have to say that from an academic point of view I was rather disappointed by the book but that may be due in part to the very high expectation that I had. As a very clearly presented, basic introduction to the subject of vehicle aerodynamics and as a source of reference the book is valuable but it left me wanting more. If that sounds a little negative I should add that I had no hesitation in ordering a copy for our university library.
R G Dominy
University of Durham