The influence of bubbles shape on acoustic behavior plays a crucial role in studying the characteristics and parameter detection of gas-liquid two-phase flow.A Monte Carlo prediction model for ellipsoidal bubbles is d...The influence of bubbles shape on acoustic behavior plays a crucial role in studying the characteristics and parameter detection of gas-liquid two-phase flow.A Monte Carlo prediction model for ellipsoidal bubbles is developed for a non-spherical bubble system,which combines the Monte Carlo method with the T-matrix method.Based on the model,the attenuation coefficient of the millimeter-sized ellipsoidal bubble cluster at the frequency of 50–500 kHz is calculated in numerical simulation,revealing the variation rules of the attenuation coefficient and the acoustic behaviors with the bubble morphology and size.The results show that,with the elongation of a bubble,the forward amplitude of the scattered sound pressure decreases and the backward amplitude increases;the scattered sound pressure exhibits angular redistribution and directional deformation depending on the incident direction.The anechoic efficiency tends to enhance with bubble elongation,particularly at low dimensionless parameters.The transmission behavior of sound waves in the bubble cluster goes down with the amplification of the major-to-minor axis ratio of the ellipsoid,while the scattering behavior exhibits the opposite trend.The attenuation coefficient climbs with both the elevation of the acoustic wave incidence angle and the major-to-minor axis ratio.Notably,when the major-to-minor axis ratio exceeds 1.1,a measurable change in attenuation coefficient occurs.The attenuation coefficient diminishes with the enlargement of bubbles,and its rate of change becomes less pronounced.For the bubble cluster with a mean radius of 2.5 mm obeying a normal distribution function,the acoustic attenuation coefficient augments as the radius distribution broadens.Specifically,when the standard deviation of this distribution is raised to 0.5 for bubbles with a radius of 2.5 mm,there is a 6.51%increase in the attenuation coefficient.展开更多
On the bases of the studies of acoustic behavior and pattern recognition of budgerigar calls, the quantitative study on characteristic parameters of acoustic behavior habits in budgerigars is further given in this pap...On the bases of the studies of acoustic behavior and pattern recognition of budgerigar calls, the quantitative study on characteristic parameters of acoustic behavior habits in budgerigars is further given in this paper. These results open up a new knowledge for comprehensive analyses of abnormalities of acoustic behavior habits in budgerigars prior to earthquakes. Under indoor lighting, the song calls in budgerigars are possessed of the beginning and ending singing time with the natural characteristics, and of the rhythmic habit of daylight singings and night rests. In daily daylight and night calls, single calls, van-toned calls, mono-syllabic and multi-syllabic protest calls are respectively possessed of the occupation habit corresponding to behavior activities, and have close acrophases and regular following properties corresponding to half-value phases, and the acrophases delay halfvalue phases by about half an hour on an average. After reversing lighting, the acrophases of budgerigar calls delay those of the normal lighting by about 12 hours on an average, and the following properties corresponding to half-value phases are irregular.展开更多
基金supported by the National Natural Science Foundation of China(52376162).
文摘The influence of bubbles shape on acoustic behavior plays a crucial role in studying the characteristics and parameter detection of gas-liquid two-phase flow.A Monte Carlo prediction model for ellipsoidal bubbles is developed for a non-spherical bubble system,which combines the Monte Carlo method with the T-matrix method.Based on the model,the attenuation coefficient of the millimeter-sized ellipsoidal bubble cluster at the frequency of 50–500 kHz is calculated in numerical simulation,revealing the variation rules of the attenuation coefficient and the acoustic behaviors with the bubble morphology and size.The results show that,with the elongation of a bubble,the forward amplitude of the scattered sound pressure decreases and the backward amplitude increases;the scattered sound pressure exhibits angular redistribution and directional deformation depending on the incident direction.The anechoic efficiency tends to enhance with bubble elongation,particularly at low dimensionless parameters.The transmission behavior of sound waves in the bubble cluster goes down with the amplification of the major-to-minor axis ratio of the ellipsoid,while the scattering behavior exhibits the opposite trend.The attenuation coefficient climbs with both the elevation of the acoustic wave incidence angle and the major-to-minor axis ratio.Notably,when the major-to-minor axis ratio exceeds 1.1,a measurable change in attenuation coefficient occurs.The attenuation coefficient diminishes with the enlargement of bubbles,and its rate of change becomes less pronounced.For the bubble cluster with a mean radius of 2.5 mm obeying a normal distribution function,the acoustic attenuation coefficient augments as the radius distribution broadens.Specifically,when the standard deviation of this distribution is raised to 0.5 for bubbles with a radius of 2.5 mm,there is a 6.51%increase in the attenuation coefficient.
文摘On the bases of the studies of acoustic behavior and pattern recognition of budgerigar calls, the quantitative study on characteristic parameters of acoustic behavior habits in budgerigars is further given in this paper. These results open up a new knowledge for comprehensive analyses of abnormalities of acoustic behavior habits in budgerigars prior to earthquakes. Under indoor lighting, the song calls in budgerigars are possessed of the beginning and ending singing time with the natural characteristics, and of the rhythmic habit of daylight singings and night rests. In daily daylight and night calls, single calls, van-toned calls, mono-syllabic and multi-syllabic protest calls are respectively possessed of the occupation habit corresponding to behavior activities, and have close acrophases and regular following properties corresponding to half-value phases, and the acrophases delay halfvalue phases by about half an hour on an average. After reversing lighting, the acrophases of budgerigar calls delay those of the normal lighting by about 12 hours on an average, and the following properties corresponding to half-value phases are irregular.
