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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)。
In this paper, two methods for recording the impulsive sound field in a fluid, the Schlieren method and the Shadowgraph method, are studied. Studies have shown that for the Schlieren method, the response of the light intensity on the imaging screen is non-linear for sound pressure and for the Shadowgraph method. Since the Shadowgrph method works without frequency constraints, it is suitable for studying the sound field of submarine models and buried objects at low ultrasonic frequencies. In this paper, Shaodowgraph method was used to record the scattered sound field of low-frequency ultrasonic pulses buried in the sand and cylinder. Five kinds of scattered waves were recorded on the half-buried body and three kinds of scattered waves were recorded on the half- Buried bodies and all buried body recorded two kinds of climbing wave (longitudinal wave climbing wave, shear wave climbing wave).