Tài liệu aerodynamics for engineering students 5e ppt

FIFI'H EDITION L E. Lo Houghton PW Carpenter Aerodynamics for Engineering Students Frontispiece (see overleaf) Aircraft wake (photo courtesy of Cessna Aircraft Company). This photograph first appeared in the Gallery of Fluid Motion, Physics of Fluids (published by the American Institute of Physics), Vol. 5, No. 9, Sept. 1993, p. S5, and was submitted by Professor Hiroshi Higuchi (Syracuse University). It shows the wake created by a Cessna Citation VI flown immediately above the fog bank over Lake Tahoe at approximately 313 km/h. Aircraft altitude was about 122 m above the lake, and its mass was approximately 8400 kg. The downwash caused the trailing vortices to descend over the fog layer and disturb it to make the flow field in the wake visible. The photograph was taken by P. Bowen for the Cessna Aircraft Company from the tail gunner’s position in a B-25 flying slightly above and ahead of the Cessna. [...]... as a steady force on the area The intensity of this ‘molecular bombardment’ force is the static pressure 6 Aerodynamics for Engineering Students Very frequently the static pressure is referred to simply as pressure The term static is rather misleading Note that its use does not imply the fluid is at rest For large bodies moving or at rest in the fluid, e.g air, the pressure is not uniform over the... [g] P 12 Aerodynamics for Engineering Students The ratio of specific heats This is a property important in high-speed flows and is defined by the equation C 7'1 CY (The value of for air depends on the temperature, but for much of practical aerodynamics it may be regarded as constant at about 1.403 This value in turn is often approximated to 7 = 1.4, which is, in fact, the theoretical value for an ideal... dimension forms the basis of dimensional analysis This is used to develop important and fundamental physical laws Its treatment is postponed to Section 1.4 later in the current chapter 4 Aerodynamics for Engineering Students Table 1.1 Units and dimensions Quantity Dimension Length Mass Time Temperature Area Volume Speed Acceleration Angle L M T Angular velocity Angular acceleration Frequency Density Force... dimensions and properties of the physical quantities used in aerodynamics then introduces common aeronautical definitions before explaining the aerodynamic forces involved and the basics of aerofoil characteristics The fundamental fluid dynamics required for the development of aerodynamics and the analysis of flows within and around solid boundaries for air at subsonic speeds is explored in depth in the... directions 8 Aerodynamics for Engineering Students 1.2.4 Temperature In any form of matter the molecules are in motion relative to each other In gases the motion is random movement of appreciable amplitude ranging from about 76 x metres under normal conditions to some tens of millimetres at very low pressures The distance of free movement of a molecule of gas is the distance it can travel before colliding... metre is a unit of length, being an actual ‘amount’ of linear displacement, and 2 Aerodynamics for Engineering Students so also is a mile The metre and mile are different units, since each contains a different m o u n t of length, but both describe length and therefore are identical dimensions.* Expressing this in symbolic form: x metres = [L] (a quantity of x metres has the dimension of length) x miles... (1.24) 13 14 Aerodynamics for Engineering Students It should be remembered that this result is obtained from the equation of state for a perfect gas and the equation of conservation of energy of the flow of a non-heatconducting inviscid fluid Such a flow behaves isentropically and, notwithstanding the apparently restrictive nature of the assumptions made above, it can be used as a model for a great... that has come to be accepted for most branches of science and engineering, and for aerodynamics in particular, in most parts of the world That system is the Systeme International d’Unitks, commonly abbreviated to SI units, and it is used throughout this book, except in a very few places as specially noted It is essential to distinguish between the terms ‘dimension’ and ‘unit’ For example, the dimension... rate at which the fluid is shearing Kinematic viscosity The kinematic viscosity (or, more properly, coefficient of kinematic viscosity) is a convenient form in which the viscosity of a fluid may be expressed It is formed - I Fig 1.3 10 Aerodynamics for Engineering *dents by combining the density p and the dynamic viscosity p according to the equation y = -P P and has the dimensions L2T-l and the units... of the same names in common use, and are defined by international agreement nt It is convenient and conventionalto represent the names of these u i sby abbreviations: kg for kilogram m for metre s for second "C for degree Celsius K for Kelvin The degree Celsius is one one-hundredth part of the temperature rise involved when pure water at freezing temperature is heated to boiling temperature at standard . (Edward Lewis) Aerodynamics for engineering students. - 5th ed. 1 Aerodynamics I Title I1 Carpenter, P.W. 629.1’323 - For information on all. w6 h1b" alt="" Aerodynamics for Engineering Students Fifth Edition E.L. Houghton and P.W. Carpenter Professor of Mechanical Engineering, The