Sound radiation patterns in the frequency domain of cries from a vespertilionid bat

1979 ◽  
Vol 134 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Finn Mogensen ◽  
Bertel M�hl
Keyword(s):  
Frequency Domain ◽  
Sound Radiation ◽  
Radiation Patterns

Classical Electrodynamics and Acoustics: Sound Radiation by Moving Multipoles

1997 ◽  
Vol 119 (2) ◽  
pp. 271-282 ◽  
Author(s):  
G. C. Gaunaurd ◽  
T. J. Eisler
Keyword(s):  
Dirac Equation ◽  
Free Field ◽  
Sound Radiation ◽  
Equation Of Motion ◽  
Rotating Machinery ◽  
Classical Electrodynamics ◽  
Radiation Patterns ◽  
Frequency Distributions ◽  
Acoustic Sources ◽  
Power Radiation

In classical electrodynamics (CED) P. Dirac used the average of retarded and advanced fields to represent the bound field and their difference to represent the free field in his derivation of the (Lorentz-Dirac) equation of motion for an electron. The latter skew-symmetric combination filtered out the radiation part of the field. It can also be used to derive many properties of the power radiated by acoustic sources, such as angular and frequency distributions. As in CED there is radiation due to source acceleration and radiation patterns exhibit the “headlight effect.” Power radiation patterns are obtained by this approach for point multipoles undergoing various motions. Applications to sound radiation problems from rotating machinery are shown. Numerous computed plots illustrate all cases.

scholarly journals k-space imaging of the eigenmodes of sharp gold tapers for scanning near-field optical microscopy

2013 ◽  
Vol 4 ◽  
pp. 603-610 ◽  
Author(s):  
Martin Esmann ◽  
Simon F Becker ◽  
Bernard B da Cunha ◽  
Jens H Brauer ◽  
Ralf Vogelgesang ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Optical Microscopy ◽  
Frequency Domain ◽  
Near Field ◽  
Higher Order ◽  
Far Field ◽  
Radiation Patterns ◽  
Background Ratio ◽  
Higher Order Modes ◽  
Spatial Frequency Domain

We investigate the radiation patterns of sharp conical gold tapers, which were designed as adiabatic nanofocusing probes for scanning near-field optical microscopy (SNOM). Field calculations show that only the lowest order eigenmode of such a taper can reach the very apex and thus induce the generation of strongly enhanced near-field signals. Higher-order modes are coupled into the far field at finite distances from the apex. Here, we demonstrate experimentally how to distinguish and separate between the lowest and higher-order eigenmodes of such a metallic taper by filtering in the spatial frequency domain. Our approach has the potential to considerably improve the signal-to-background ratio in spectroscopic experiments at the nanoscale.

Non-impulsive signal deconvolution for computation of violin sound radiation patterns and applications in sound synthesis

2015 ◽  
Vol 138 (3) ◽  
pp. 1785-1785
Author(s):  
Alfonso Perez Carrillo ◽  
Jordi Bonada ◽  
Vesa Valimaki ◽  
Andres Bucci ◽  
Jukka Patynen
Keyword(s):  
Sound Radiation ◽  
Sound Synthesis ◽  
Radiation Patterns ◽  
Signal Deconvolution

Sound Radiation From a Finite Cylindrical Shell Covered With a Compliant Layer

1991 ◽  
Vol 113 (2) ◽  
pp. 267-272 ◽  
Author(s):  
B. Laulagnet ◽  
J. L. Guyader
Keyword(s):  
Cylindrical Shell ◽  
Frequency Domain ◽  
Mathematical Analysis ◽  
Strong Influence ◽  
Sound Radiation ◽  
Radiated Power ◽  
Shell Motion ◽  
Compliant Layer ◽  
Finite Cylindrical Shell ◽  
Large Frequency

The aim of this work is to present the mathematical analysis and numerical results about sound radiation from a finite cylindrical shell covered with a compliant layer, immersed in water. The shell motion is obtained using Flu¨gge’s operator whereas the layer is described by a locally reacting material. The results are presented both in shell radial quadratic velocity and radiated power. Two major conclusions can be drawn when looking at results: (1) a reasonable stiffness layer allows one to reduce the radiated power in a large frequency domain; (2) the layer has a strong influence on the shell velocity which exhibits an antiresonance phenomenon when covered.

Classical Electrodynamics and Acoustics, Part 2: Sound Radiation by Moving Quadrupoles

1999 ◽  
Vol 121 (1) ◽  
pp. 126-130 ◽  
Author(s):  
G. C. Gaunaurd ◽  
T. J. Eisler
Keyword(s):  
Sound Radiation ◽  
Classical Electrodynamics ◽  
Radiation Patterns

Our earlier work in Part 1 of this paper [1] is here extended to quadrupole distributions and point quadrupoles (i.e., stresses) in arbitrary motion. Radiation patterns are obtained and displayed in many relevant cases.

Sign in / Sign up

Export Citation Format

Share Document