Visualization of the sound scattering by a cylinder

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.