Linearized Theory of Steady High-Speed Flow


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Originally published in 1955, this book is devoted exclusively to the problems involved in solving the non-linear equations of motion for compressible fluids.













Elements of Gas Dynamics


Book Description

The increasing importance of concepts from compressible fluid flow theory for aeronautical applications makes the republication of this first-rate text particularly timely. Intended mainly for aeronautics students, the text will also be helpful to practicing engineers and scientists who work on problems involving the aerodynamics of compressible fluids. Covering the general principles of gas dynamics to provide a working understanding of the essentials of gas flow, the contents of this book form the foundation for a study of the specialized literature and should give the necessary background for reading original papers on the subject. Topics include introductory concepts from thermodynamics, including entropy, reciprocity relations, equilibrium conditions, the law of mass action and condensation; one-dimensional gasdynamics, one-dimensional wave motion, waves in supersonic flow, flow in ducts and wind tunnels, methods of measurement, the equations of frictionless flow, small-perturbation theory, transonic flow, effects of viscosity and conductivity, and much more. The text includes numerous detailed figures and several useful tables, while concluding exercises demonstrate the application of the material in the text and outline additional subjects. Advanced undergraduate or graduate physics and engineering students with at least a working knowledge of calculus and basic physics will profit immensely from studying this outstanding volume.




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Fluid Dynamics / Strömungsmechanik


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Sect 2. 317 tinuity surfaces 1. This suggests that a wake pressure Pw be associated with each flow past a bluff body, and that a wake parameter (2. 4) which plays the same role as the cavitation parameter (2. 1), be defined for the flow. This idea has been made the basis of a modified wake theory (ef. Sect. 11) which proves to be in good qu- titative agreement with pressure and drag measurements. It should be emphasized, however, that un h like the cavitation number, the wake parameter is a quantity which is not known a priori, and must be empirically determined in each case. (3) Jet flows. The problem of jet efflux from an orifice is one of the oldest in hydrodynamics and the first to be treated by Fig. 3a. the HELMHOLTZ free streamline theory. Of particular importance for engineering applications is the discharge coefficient Cd' which is defined in terms of the discharge Q per unit time, the pressure P, and the cross-sectional area A of the orifice, by the formula, (2. 5) where e is the fluid density. Two methods of measuring Cd have been most fre quently adopted. In the first the liquid issues from an orifice in a large vessel under the influence of gravity _,-____________ . , (Fig. 3 a), while in the second it 1 L is forced out of a nozzle or pipe under high pressure (Fig. 3 b).




Expected Number of Maxima and Minima of a Stationary Random Process with Non-Gaussian Frequency Distribution


Book Description

A method is outlined for calculating the expected number of maxima or minima of a random process with non-Gaussian frequency distribution from the statistical moments of the process and its first two derivatives. This method is based on an estimate of the joint frequency function of the process and its first two derivatives given by mesm of a generalized form of Edgeworth's series; the procedure thus consists essentially in applying a correction to the results for a Gaussian process. The functions required in this procedure are calculated for the first two correction terms; therefore, the effects of skewness and kurtosis can be calculated, provided the required moments are known. Expressions are given for these moments in terms of multiple correlation functions and multi-spectra, and the relations between these functions for a random output of a linear system and those for the random input are indicated.