Rayleigh and Lamb Waves on Cylinders.

Acoustic waves propagating on the surface of solid and hollow elastic cylinders immersed in water were observed and their characteristics shown to be consistent with theory. These waves were excited by an 11-μsec pulse, projected onto the cylindrical surface at an excitation angle given by sin 1(co/cs), where co is the velocity of sound in water and cs is the velocity of the surface wave. The waves may be observed, since they continually radiate energy back into the water at the excitation angle. Surface waves were observed to exist on pure (98%) aluminum, 304 stainless steel, and various aluminum-alloy cylinders. Circumference-to-wavelength ratios were varied from 10 to 400 to discern the dispersive effects owing to the curvature of the target. It was also found that inhomogeneities correlate with pure propagation characteristics in some of the targets. The waves observed on air- and water-filled cylinders immersed in water are shown to correspond to the symmetric and antisymmetric vibrations in the shell. [ABSTRACT FROM AUTHOR]