Based upon the theoretical analysis of the sound field in a finite duct and the spatialsampling principle,this paper applies the adaptive filtering technique to the measurement of thesound field in the duct with the d...Based upon the theoretical analysis of the sound field in a finite duct and the spatialsampling principle,this paper applies the adaptive filtering technique to the measurement of thesound field in the duct with the distribution patterns of standing waves in the direction of thewaveguide and high—order wavefront on the cross section of the duct measured and the acousticmode theory proved by experimental results.展开更多
Spatial distribution of acoustic and elastic waves generated by an elementary vibration source at seismic profiling frequencies in an infinite medium close to a layer inclusion, i.e., an extended layer, is numerically...Spatial distribution of acoustic and elastic waves generated by an elementary vibration source at seismic profiling frequencies in an infinite medium close to a layer inclusion, i.e., an extended layer, is numerically simulated. Point dipole radiation in a homogeneous infinite medium separated by a liquid layer of different medium density or acoustic wave velocity is considered. Transverse elastic SH-waves excited by an oscillating power source in a solid medium also located close to the layer of different propagation velocity than the velocity of the vicinity are analyzed. Formulae for the spatial distribution of the wave field amplitude are derived and computer graphics of field distribution images is presented. Wave reflection, penetration deep into the layer inclusion, and transmittance through it are examined. Results of the analysis can be applied to seismoacoustic probing of geologic environment by the near field of a harmonic vibration source.展开更多
The horizontal-longitudinal correlation of acoustic field for the receiver near the bottom is analyzed by using nu- merical modeling. An approximate analytical solution of horizontal-longitudinal correlation coefficie...The horizontal-longitudinal correlation of acoustic field for the receiver near the bottom is analyzed by using nu- merical modeling. An approximate analytical solution of horizontal-longitudinal correlation coefficient is derived based on the ray method. Combining the characteristic of Lloyd's mirror interference pattern, the variability of acoustic field and its effect on horizontal-longitudinal spatial correlation are discussed. The theoretical pre- diction agrees well with the numerical results. Experimental results confirm the validity of analytical solution. Finally, the applicability of the analytical solution is summarized. The conclusion is beneficial for the design of bottom-moored array and the estimation of integral time for moving source localization.展开更多
文摘Based upon the theoretical analysis of the sound field in a finite duct and the spatialsampling principle,this paper applies the adaptive filtering technique to the measurement of thesound field in the duct with the distribution patterns of standing waves in the direction of thewaveguide and high—order wavefront on the cross section of the duct measured and the acousticmode theory proved by experimental results.
文摘Spatial distribution of acoustic and elastic waves generated by an elementary vibration source at seismic profiling frequencies in an infinite medium close to a layer inclusion, i.e., an extended layer, is numerically simulated. Point dipole radiation in a homogeneous infinite medium separated by a liquid layer of different medium density or acoustic wave velocity is considered. Transverse elastic SH-waves excited by an oscillating power source in a solid medium also located close to the layer of different propagation velocity than the velocity of the vicinity are analyzed. Formulae for the spatial distribution of the wave field amplitude are derived and computer graphics of field distribution images is presented. Wave reflection, penetration deep into the layer inclusion, and transmittance through it are examined. Results of the analysis can be applied to seismoacoustic probing of geologic environment by the near field of a harmonic vibration source.
基金Supported by the National Natural Science Foundation of China under Grant No 11174235
文摘The horizontal-longitudinal correlation of acoustic field for the receiver near the bottom is analyzed by using nu- merical modeling. An approximate analytical solution of horizontal-longitudinal correlation coefficient is derived based on the ray method. Combining the characteristic of Lloyd's mirror interference pattern, the variability of acoustic field and its effect on horizontal-longitudinal spatial correlation are discussed. The theoretical pre- diction agrees well with the numerical results. Experimental results confirm the validity of analytical solution. Finally, the applicability of the analytical solution is summarized. The conclusion is beneficial for the design of bottom-moored array and the estimation of integral time for moving source localization.