Tables of Characteristic Functions for Solving Boundary-value Problems of the Wave Equation with Application to Supersonic Interference

Tables of Characteristic Functions for Solving Boundary-value Problems of the Wave Equation with Application to Supersonic Interference

Author: Jack Norman Nielsen

Publisher:

Published: 1957

Total Pages: 682

ISBN-13:

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Tables are presented containing 69,000 values of a set of characteristic functions which first arose in problems of supersonic wing-body interference. The tables are useful in problems of supersonic flow involving aerodynamic shapes which are wholly or in part quasi-cylinders of nearly circular cross section. A number of uses are described in the aerodynamics of bodies alone, body-body or shock-body interference, wing-body interference, the vortex-panel interference. Three illustrative examples are worked out in detail. First, the pressure field due to fuselage indentation is calculated and presented in a form independent of Mach number. Secondly, the tables are applied to a problem involving a previously unpublished solution to the Navier-Stokes equations; namely, the boundary-layer profiles of a circular cylinder moved impulsively with a constant axial force in a viscous incompressible fluid. In the final example, the wave drag of corrugated circular cylinders is calculated as a function of the number of corrugations and their wave length. Several nonaerodynamic applications are pointed out in the fields of acoustics and heat conduction. Generally speaking, the tables are applicable to boundary-value problems of the second kind involving the wave equation in three dimensions with approximately circular cylindrical boundaries or involving the unsteady heat-conduction equation in two space dimensions with nearly circular boundaries.


Turbojet Engine Noise Reduction with Mixing Nozzle-ejector Combinations

Turbojet Engine Noise Reduction with Mixing Nozzle-ejector Combinations

Author: Willard D. Coles

Publisher:

Published: 1958

Total Pages: 652

ISBN-13:

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Several noise suppressors consisting of combinations of mixing nozzles and ejectors were tested on two full-scale turbojet engines. Maximum sound pressure level reductions of 12 decibels and sound power level reductions of 8 decibels were obtained. The ejectors provided 3 to 5 decibels of the sound power reduction. The effects of ejector dimensions on noise suppression and engine performance were investigated. Ejector lengths of approximately 2.0 standard nozzle diameters and ejector diameters larger than 1.6 standard nozzle diameters provided the greatest additional noise reduction to that obtained with the mixing nozzles alone. The ejector can restore the static thrust loss caused by use of the mixing nozzle or can provide static-thrust augmentation.


Combustion and Mass Transfer

Combustion and Mass Transfer

Author: D Brian Spalding

Publisher: Elsevier

Published: 2013-10-22

Total Pages: 419

ISBN-13: 1483136353

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Combustion and Mass Transfer: A Textbook with Multiple-Choice Exercises for Engineering Students is a 20-chapter lecture text that covers various aspects of combustion and mass transfer. Each of the 20 chapters is provided with a set partly analytical and multiple-choice tutorial exercises, designed to assist the student to understand the material of the lectures. The opening chapters deal with the importance of combustion and mass transfer processes. The succeeding chapters survey the concepts and principles of droplet vaporization, droplet combustion, liquid-propellant rocket, and laminar and turbulent jet. These topics are followed by discussions of laminar and turbulent diffusion flame, kinetically-influenced phenomena, chemical kinetics, and spontaneous ignition. The remaining chapters consider the basic concepts of stirred reactor, flame stabilization, laminar flame propagation, spark ignition, and coal-particle combustion. This book is intended for undergraduate mechanical engineering students.