柱体散射的声场显示

Visualization of the sound scattering by a cylinder

本文应用schlieren显示方法,对有限长圆柱体在单一液体及有分层界面的两液层中声波垂直入射和斜入射的回波结构以及界面对回波结构的影响作了实验研究,实验用图象显示了影区内不连续处产生的回波,我们利用这一结果,成功地描绘了螺旋表面波的轨迹,从而实现了应用schlieren法来阐明三维声场的途径,避免了需要用庞大设备和复杂运算的三维显示技术。

The schlieren method is used to visualize the sound scattering of a cylinder immersed in liquid, images of the echoes, caused by normal and oblique incidence from a cylinder, are obtained for two kinds of liquid: (1) the liquid is composed a transparent liquid and (2) the liquid is composed of two non-mixable transparent liquids. It is found experimentally that the echo can be caused by the discontinuity in the shadow zone. This fact is utilized to demonstrate the locus of the helical surface wave creeping along the surface of the cylinder. For such cases the three-dimensional image can be described by this method and has not need to use the system with special appliances and complex algorithm.