利用体视显微镜和驻波管吸声系数测试仪,对长耳鸮、雉鸡、鸽子的胸腹部皮肤和覆羽进行形态、结构观察测试及吸声降噪特征对比试验,并试验研究了长耳鸮皮肤组织试样的耦合吸声特征。结果表明,长耳鸮皮肤和覆羽具有独特的多层次形态与结构耦合特征;在测试频率范围内,三种鸟类皮肤和覆羽的吸声能力在低频段(1000Hz以下)无明显差异,在高频段(1000Hz-4000Hz),长耳鸮皮肤和覆羽呈现一定的吸声性能,其吸声系数最大值可达0.45,而雉鸡和鸽子体表吸声性较差。根据长耳鸮体表耦合降噪特征运用微穿孔板吸声体吸声系数计算理论,建立仿生耦合吸声数值模型,分析其形态与结构耦合特征的吸声机理。
The sound absorption coefficients of the chest and abdominal skin and feather for avians, including longeared owl, pheasant and pigeon, were tested using standing wave method, and their sound absorption properties were compared, The results showed that the longeared owl surface possess the structure and form with coupling characteristic. The sound absorption coefficients of the aves species did not change evidently below 1000 Hz, but at the tested frequency range (1000-2000 Hz) their sound absorption coefficients increased with the increase frequency, the peak value of sound absorption coefficient is up to 0.45. The sound absorption property of the sample for longeared owl at high frequency is better than that of other two species. The sound absorption coefficient of the sample with the feather and skin coupling is higher than that of simplex configuration. It is concluded that the chest and abdominal skin and feather sound absorption properties of longeared owl is affected by its structure and shape coupling of surface. Based on long-eared owl surface coupling characteristics and the micro-perforated panel absorber theory, the absorption coefficient coupling model is established to analyze the sound absorption characteristics of the coupling mechanism.