Nero R W, Feuillade C, Thompson C H, Love R H
Naval Research Laboratory, Stennis Space Center, Mississippi 39529-5004, USA.
J Acoust Soc Am. 2007 Jan;121(1):132-43. doi: 10.1121/1.2382277.
The air-filled swimbladders of fish resonate like damped air bubbles, and are very efficient acoustic scatterers at low to mid frequencies (typically <20 kHz). Scattering experiments were performed on an artificial "fish school" constructed from polyethylene bubbles. A mathematical model, developed to describe near-resonance backscattering from schooling fish [J. Acoust. Soc. Am. 99, 196-208 (1996)], was used to analyze the physical behavior for three different arrays of these bubbles. The measurements gave excellent agreement with the model, showing that coupled-resonance and interference effects cause the frequency response of tightly packed arrays, with spacing corresponding to the order of a body length for fish, to differ significantly from those of more dispersed arrays. As the array spacing is increased to the equivalent of several body lengths, these effects rapidly diminish. The results of this comparison demonstrate that, at low to mid frequencies, coupled resonance and interference effects are likely in schooling fish, and need to be considered in applications of underwater acoustic methods to the study of fish populations.
鱼类充满空气的鱼鳔像阻尼气泡一样产生共振，并且在低频到中频（通常<20 kHz）时是非常高效的声学散射体。在由聚乙烯气泡构成的人工“鱼群”上进行了散射实验。一个用于描述鱼群近共振后向散射的数学模型[《美国声学学会杂志》99, 196 - 208 (1996)]被用来分析这三种不同气泡阵列的物理行为。测量结果与模型高度吻合，表明耦合共振和干涉效应使得紧密排列阵列（间距相当于鱼的体长量级）的频率响应与更分散阵列的频率响应有显著差异。当阵列间距增加到相当于几个体长时，这些效应迅速减弱。该比较结果表明，在低频到中频时，鱼群中可能存在耦合共振和干涉效应，并且在将水下声学方法应用于鱼类种群研究时需要考虑这些效应。
