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对记录脉冲声场的光学方法及对沙中埋藏的类圆柱体的散射声场的研究 总被引:1,自引:0,他引:1
本文对用于记录流体中脉冲声场的两种方法——Schlieren法和Shadowgraph法的响应进行了研究。研究表明对于Schlieren法,成像屏上的光强的响应对于声压是非线性关系;对于 Shadowgraph法来说,则是线性关系。由于 Shadowgrph法的工作不受频率限制,适用于在低超声频下研究海底模型和埋藏物的声场。本文利用Shaodowgraph法记录了埋在沙中圆柱体、类圆柱体的低超声频脉冲的散射声场,对半埋体记录到5种散射波,对全埋体则记录到3种散射波,对半埋体与全埋体都记录到两种爬波(纵波爬波、横波爬波)。 相似文献
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Visual-Width of an Ultrasonic Gaussian Beam on the Schlieren Photograph and Explanation to the Nonspecularly Reflected Sound Field 下载免费PDF全文
On the Schlieren photograph,a continuous ultrasonic Gaussian beam and its nonspecularly reflected beams [Chin.Phys.Lett.16 (1999)819] always have limited visual-width,although the theoretical spatial distribution of the sound field is a continuous function.To study this problem,the first step is to investigate the visual-width of the beam on the photograph related to the sound pressure at the centre of the beam by the threshold of the optical system caused by the refraction of light;the second step is to explain the visual-width of nonspecularly reflected field.By applying a relevant threshold,checked by the visual width of the incident beam,to cut the theoretical curves of the reflected sound field,one can find the visual-width of the two reflected beams and the gap between them correspond to that on the Schlieren photograph. 相似文献
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