Circumferential Waves in Thin-Walled Air-Filled Cylinders in Water

Experimental measurements of the velocity and the rate of decay of circumferential waves traveling within the shells of thin-walled air-filled metallic cylinders in water have been made. Outside diameters of 3.5, 5.5, 8.5, and 12 in. were studied. Ratios of d (shell thickness) to λ (wavelength) of 0.01 to 0.97 were obtained over a frequency range of 80 to 300 kc. The measured velocities are compared with the theoretical velocities for the longitudinal and flexural modes in infinite plates. The agreement obtained defines the nature of the waves measured and supports the analogy of an infinite plate applied to the cylindrical surfaces. Empirical relations describing the decay measurements are given.