摘要:

Significant factors of the sonic‐boom problem are shown to be numerous and to involve a variety of scientific and engineering disciplines. Special mention is made of the rôles of aircraft design, aircraft operations, and the atmosphere in affecting the sonic‐boom ground exposures and the effects of sonic booms on people, buildings, etc. The material of this paper is introductory to the more detailed discussions that follow.

ISSN:0001-4966    

DOI:10.1121/1.1914037

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

Current theoretical methods of estimating the flow field surrounding airplanes in supersonic flight are based on Whitham's solution for the flow about bodies of revolution and on other theoretical work that makes possible the representation of a complete airplane as an equivalent body of revolution. This paper presents a review of the fundamental theory and discusses the use of high‐speed digital computers in providing rapid and reliable analysis of sonic‐boom characteristics of complex airplane configurations. Application of the estimation techniques is illustrated in correlation with wind‐tunnel and flight‐test measurements.

ISSN:0001-4966    

DOI:10.1121/1.1914038

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

This paper reviews, through detailed consideration of airplane configuration, theoretically based techniques for minimization of sonic‐boom pressure‐field energy and overpressure. The discussion includes consideration of the recently discovered potential for overpressure minimization for large slender airplanes with extended nearfield characteristics. Use of the latter method is illustrated with correlations of theory and wind‐tunnel measurements.

ISSN:0001-4966    

DOI:10.1121/1.1914039

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

A recent theoretical development to describe the propagation of weak shock waves through a nonuniform media has been used to investigate the effect of stratified atmospheric models on the sonic boom generated by an airplane in steady level flight. Effects of variations in temperature, pressure, and winds with altitude on the strength, lateral distribution, and extent of the shock waves on the ground are discussed. Comparisons of theoretical results with flight‐test data are presented.

ISSN:0001-4966    

DOI:10.1121/1.1914040

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

Special considerations are involved in the selection of instrumentation for meaningful sonic‐boom measurements. Because of the nature of the sonic‐boom pressure signature, the requirements include usable frequency response from nearly dc to several thousand cycles per second in the pressure range 0.1 to 10 lb/sq ft. A specially developed NASA instrument system is described along with techniques of measurement. The problems of vibration isolation, wind screening, long cable lengths, and field calibrations are discussed, and some sample data are presented.

ISSN:0001-4966    

DOI:10.1121/1.1914041

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

This paper is a report on the state of knowledge of sonic‐boom phenomena. The pressure buildups in the transonic‐speed range and the lateral extent of the pattern in steady flight for quiescent atmospheric conditions are described. Also discussed are recent data from flight‐test studies relating to atmospheric dynamic effects on the sonic‐boom signatures. The acceleration and lateral‐spread phenomena appear to be fairly well understood and predictable for current and future aircraft. Variations in the sonic‐boom signature as a result of the effects of the atmosphere can be expected during routine operations. From the data evaluated to date, very similar variations in pressure signatures are noted for both fighter and bomber aircraft.

ISSN:0001-4966    

DOI:10.1121/1.1914042

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

This introduction to the second part of the Sonic‐Boom Symposium reviews the history of observations on human reactions to the sonic boom from the time when the boom was a demonstration curiosity to the present day where reaction of the population to the sonic boom is a scientific problem of technical, economic, social, and political consequences at the national and international level. The field programs conducted by the USAF and NASA over the last 15 years and over the last 5 years by the FAA were all of limited scope with respect to exploring direct and indirect physiological and psychological human reactions to sonic booms of different intensity and exposure frequency. Although the data accumulated might be adequate to decide on preliminary stopgap exposure criteria, it is obvious that a broader approach to the problem is required. Laboratory work in support of these questions has hardly been started. Neither conventional acoustic and vibration generators for boom‐type stimulation nor special equipment for high‐fidelity sonic‐boom simulation have been fully utilized. Some of the open questions and possible approaches are discussed as part of a broad, long‐range research program required to come up with scientific data as bases for operational sonic‐boom exposure criteria.

ISSN:0001-4966    

DOI:10.1121/1.1914043

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

The vicinity of St. Louis, Missouri, was exposed to approximately 150 sonic booms during a 10‐month period from July 1961 to April 1962. Ground overpressures, ranging up to about 3 lb/sq ft. were carefully measured for a series of 17 of the supersonic flights. Data obtained from over 2300 direct interviews, analyses of complaints, and engineering evaluations of alleged damage were related to information on aircraft operations and sonic‐boom overpressure measurements. Most residents interviewed indicated some interference with routine living activities, yet less than 1% filed formal complaints. Alleged building damage was superficial in nature and consisted mostly of cracks in brittle surfaces. There were no reports of direct adverse physiological effects.

ISSN:0001-4966    

DOI:10.1121/1.1914044

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

Over the past five years, a number of exercises involving the making of bangs have been staged in the United Kingdom. The bangs have been made both by flying aircraft at supersonic speeds and by firing explosive charges. From this work, information has been obtained on the intensities and waveforms of aircraft sonic bangs as measured outdoors, on the nature of the disturbances that are recorded inside buildings, and on the subjective reactions of people to these bangs. The paper summarizes the results of this work.

ISSN:0001-4966    

DOI:10.1121/1.1914045

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP

摘要:

Investigations of the physiological psychological responses to impulsive acoustic stimuli and to sonic booms at the intensities anticipated from commercial supersonic aircraft have been conducted in the laboratory. Studies of interest include those concerned with (a) the relative subjective noisiness and loudness of booms having different wavefronts; (b) the reactions of people to booms as an auditory experience (subjective rating of booms versus other acoustical stimuli); (c) startle reactions to acoustic stimuli; and (d) arousal from sleep by acoustic stimuli. The methods and results of pertinent laboratory experiments are discussed.

ISSN:0001-4966    

DOI:10.1121/1.1914046

出版商:Acoustical Society of America    

年代:1966

数据来源: AIP