摘要:

A theory of jet noise is developed from the observation that in low‐speed turbulence Lighthill's quadrupoles combine to behave like simple sources ∼∂2p(0)/∂t2, wherep(0)is the “incompressible” local pressure in the turbulence. An integral for the far‐field intensity involves the space‐time pressure covarianceRwithin the turbulent. Choice ofRin a worked example shows how pronounced directionality results from pattern “convection” (modified by fluctuation) in conjunction with the time retardation. Further directionality is accounted for in terms of a Green's function (discussed qualitatively but not worked out) for a point source at rest in the mean shear flow, describing the lateral refraction and diffraction.

ISSN:0001-4966    

DOI:10.1121/1.1907702

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907703

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

摘要:

The measurement of ultrasonic cleaning as a function of the gas content of the media is described. A positive relationship between cleaning and gas content is noted.

ISSN:0001-4966    

DOI:10.1121/1.1907704

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

摘要:

The tube method has been used to extend measurements of sound absorption in carbon dioxide to 300°C. Results indicate that all of the vibrational specific heat inCO2relaxes with a single relaxation time. This relaxation time at 305°C was found to be 3.05 ×10−6sec.

ISSN:0001-4966    

DOI:10.1121/1.1907705

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

摘要:

A technique, involving use of a thermistor imbedded in a plane surface, is described for measuring viscous heating and microstreaming in acoustic boundary layers.

ISSN:0001-4966    

DOI:10.1121/1.1907706

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907709

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.1907710

出版商:Acoustical Society of America    

年代:1959

数据来源: AIP