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The Library Shelf

The Library Shelf given. Chapter five describes the various approxi­ mate methods which have been used for calcu­ lating the flow of a compressible fluid past a body, including the derivation of the well known Prandtl-Glauert law and von Karman's applica­ The First British Book on Air Flow tion of the hodograph method. This is followed by an account of the method used for calculating at High Speeds is Published by AIRCRAFT ENGINEERING the critical Mach number of a wing or body from the low speed pressure distribution, using either the Prandtl-Glauert or Karman formula. An Introduction to Aerodynamic Compressibility. for a book giving a concise introduction to the A short account of the theory of supersonic flow By J. Black. [AIRCRAFT ENGINEERING (Bun- subject, to enable the aircraft designer to read is then given, including the Prandtl-Meyer ex­ hill Publications Ltd.) 18s. Postage 1s.) and understand the current reports dealing with pansion and the characteristics method as des­ recent developments, and to provide the scientific It is now well known among aircraft engineers cribed by Busemann. The application of the background which is so necessary for good de­ that the compressibility of the air has an increas­ characteristics method to the design of super­ sign. ingly important effect on the aerodynamic forces sonic nozzles is also considered. In the final Mr Black's book, the first of its kind to be as the flight speed rises and approaches the speed chapter a brief account is given of the properties published in this country, gives a most useful in­ of sound. As a result of the development of the of aerofoils at high speeds and some problems troduction to the problems of air flow at high gas turbine and other improvements, aircraft of high speed aircraft design. An appendix gives speeds. Alhough the interests of the aircraft en­ speeds have risen very rapidly during the last few a short description of the three optical methods gineer have been kept in mind, the book deals years, and compressibility effects are, therefore, which have been used for investigating high mainly with fundamental physical principles, of great importance in many new aircraft de­ speed air flow; direct shadow, 'schlieren' and and it should be of considerable interest to any signs. Unfortunately, the designer is faced with interference photography. The book deals with engineer dealing with the high speed flow of air very great difficulties in attempting to predict the a subject that is advancing very rapidly at pre­ or other gases, e.g. in turbines and compressors. behaviour of a new aircraft flying at high speeds. sent, and hence it is only to be expected that Advanced mathematics have been avoided, and The main reason for this is simply that there is some parts of it should already appear obsolete. most students and engineers should find no dif­ very little systematic knowledge of air flow at This situation was probably aggravated by war­ ficulty in reading and understanding it. high speeds past wings and bodies. A further dif­ time restrictions which prevented the author ficulty arises because many of the methods and The first chapter deals with the propagation of from seeing the results of the latest experimental ideas which have proved so useful in the design sound waves and shows how the velocity of work. of low speed aircraft may have to be changed sound in air depends only on the temperature. There are a few errors and omissions, but completely when high speeds are considered. To The Mach number and Mach angle are defined most of these are not important and do not seri­ mention only one example, it is well known that and their significance is explained. This is fol­ ously reduce the value of the book. The nomen­ at low speeds a separation of the boundary layer lowed by a chapter dealing with the equations clature used by the author does not always agree at the rear of an aerofoil causes an increase of of motion of a compressible fluid in two dimen­ with standard usage and this may occasionally drag, but is not so well known that a separation sions, Bernoulli's equation and some simple ther­ cause some confusion to a reader who is not of the same kind at supersonic speeds causes a modynamic relations. The use of thermodyna­ familiar with the subject. In a few places, where reduction of drag (for a given incidence). Be­ mic diagrams such as the Mollier diagram is ex­ only a very short and rather incomplete explana­ cause there may be differences as important as plained, and theoretical methods for calculating tion is given for some phenomenon, it might this between high and low speeds it is not enough 'one-dimensional' flow in nozzles are described. perhaps have been better to omit the explana­ that the designer should merely modify his pre­ In the next chapter the flow in nozzles is con­ tion altogether unless it could be given more sent methods and ideas to allow for compressi­ sidered in more detail, and the various flows space. bility; he must regard the design problems of which are possible after the throat in a conver­ The book is clearly written and is free from high speed flight as completely new ones, and gent-divergent nozzle are described. This is fol­ unnecessary descriptive details. It is well illus­ acquire a new scientific background to deal with lowed by a brief description of some high speed trated by a large number of line drawings and them. It is important that the designer of high wind tunnels which have been used in different nine half-tone plates. The index is very good and speed aircraft should have a sound knowledge of countries. The next chapter considers the pro­ complete. References to original papers are the fundamental principles of air flow at high perties of shock waves, and gives the equation to given whenever possible and these should serve speeds. Unfortunately, much of the information be used for calculating the changes of velocity, as a most useful guide to more advanced read­ which is available on this subject is scattered pressure and stream direction for both normal ing on the subject. The book can be confidently among a large number of books and reports, and and oblique shock waves. Diagrams for the recommended as an introduction to high speed is not easily accessible. Thus there is a great need rapid determination of these quantities are also aerodynamics. W. A. M. 20 Aircraft Engineering http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

The Library Shelf

Aircraft Engineering and Aerospace Technology , Volume 20 (1): 1 – Jan 1, 1948

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb031591
Publisher site
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Abstract

given. Chapter five describes the various approxi­ mate methods which have been used for calcu­ lating the flow of a compressible fluid past a body, including the derivation of the well known Prandtl-Glauert law and von Karman's applica­ The First British Book on Air Flow tion of the hodograph method. This is followed by an account of the method used for calculating at High Speeds is Published by AIRCRAFT ENGINEERING the critical Mach number of a wing or body from the low speed pressure distribution, using either the Prandtl-Glauert or Karman formula. An Introduction to Aerodynamic Compressibility. for a book giving a concise introduction to the A short account of the theory of supersonic flow By J. Black. [AIRCRAFT ENGINEERING (Bun- subject, to enable the aircraft designer to read is then given, including the Prandtl-Meyer ex­ hill Publications Ltd.) 18s. Postage 1s.) and understand the current reports dealing with pansion and the characteristics method as des­ recent developments, and to provide the scientific It is now well known among aircraft engineers cribed by Busemann. The application of the background which is so necessary for good de­ that the compressibility of the air has an increas­ characteristics method to the design of super­ sign. ingly important effect on the aerodynamic forces sonic nozzles is also considered. In the final Mr Black's book, the first of its kind to be as the flight speed rises and approaches the speed chapter a brief account is given of the properties published in this country, gives a most useful in­ of sound. As a result of the development of the of aerofoils at high speeds and some problems troduction to the problems of air flow at high gas turbine and other improvements, aircraft of high speed aircraft design. An appendix gives speeds. Alhough the interests of the aircraft en­ speeds have risen very rapidly during the last few a short description of the three optical methods gineer have been kept in mind, the book deals years, and compressibility effects are, therefore, which have been used for investigating high mainly with fundamental physical principles, of great importance in many new aircraft de­ speed air flow; direct shadow, 'schlieren' and and it should be of considerable interest to any signs. Unfortunately, the designer is faced with interference photography. The book deals with engineer dealing with the high speed flow of air very great difficulties in attempting to predict the a subject that is advancing very rapidly at pre­ or other gases, e.g. in turbines and compressors. behaviour of a new aircraft flying at high speeds. sent, and hence it is only to be expected that Advanced mathematics have been avoided, and The main reason for this is simply that there is some parts of it should already appear obsolete. most students and engineers should find no dif­ very little systematic knowledge of air flow at This situation was probably aggravated by war­ ficulty in reading and understanding it. high speeds past wings and bodies. A further dif­ time restrictions which prevented the author ficulty arises because many of the methods and The first chapter deals with the propagation of from seeing the results of the latest experimental ideas which have proved so useful in the design sound waves and shows how the velocity of work. of low speed aircraft may have to be changed sound in air depends only on the temperature. There are a few errors and omissions, but completely when high speeds are considered. To The Mach number and Mach angle are defined most of these are not important and do not seri­ mention only one example, it is well known that and their significance is explained. This is fol­ ously reduce the value of the book. The nomen­ at low speeds a separation of the boundary layer lowed by a chapter dealing with the equations clature used by the author does not always agree at the rear of an aerofoil causes an increase of of motion of a compressible fluid in two dimen­ with standard usage and this may occasionally drag, but is not so well known that a separation sions, Bernoulli's equation and some simple ther­ cause some confusion to a reader who is not of the same kind at supersonic speeds causes a modynamic relations. The use of thermodyna­ familiar with the subject. In a few places, where reduction of drag (for a given incidence). Be­ mic diagrams such as the Mollier diagram is ex­ only a very short and rather incomplete explana­ cause there may be differences as important as plained, and theoretical methods for calculating tion is given for some phenomenon, it might this between high and low speeds it is not enough 'one-dimensional' flow in nozzles are described. perhaps have been better to omit the explana­ that the designer should merely modify his pre­ In the next chapter the flow in nozzles is con­ tion altogether unless it could be given more sent methods and ideas to allow for compressi­ sidered in more detail, and the various flows space. bility; he must regard the design problems of which are possible after the throat in a conver­ The book is clearly written and is free from high speed flight as completely new ones, and gent-divergent nozzle are described. This is fol­ unnecessary descriptive details. It is well illus­ acquire a new scientific background to deal with lowed by a brief description of some high speed trated by a large number of line drawings and them. It is important that the designer of high wind tunnels which have been used in different nine half-tone plates. The index is very good and speed aircraft should have a sound knowledge of countries. The next chapter considers the pro­ complete. References to original papers are the fundamental principles of air flow at high perties of shock waves, and gives the equation to given whenever possible and these should serve speeds. Unfortunately, much of the information be used for calculating the changes of velocity, as a most useful guide to more advanced read­ which is available on this subject is scattered pressure and stream direction for both normal ing on the subject. The book can be confidently among a large number of books and reports, and and oblique shock waves. Diagrams for the recommended as an introduction to high speed is not easily accessible. Thus there is a great need rapid determination of these quantities are also aerodynamics. W. A. M. 20 Aircraft Engineering

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: Jan 1, 1948

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