A*-wave spatial resonances on thin cylindrical shells: Experimental study

Abstract

An experimental study of a thin cylindrical shell in contact with two different fluids is proposed. Using surface wave analysis methods (SWAM), the A-wave and A*-wave attenuation and phase velocity are first measured. The experiments show that when the internal fluid has a sound velocity slower than the external fluid, internal reflection of energy inside the shell generates an A*-wave in multiple space and time positions. Using those results as a basis hypothesis, the 2-D Ksi(k,ω) wave-number-frequency response of the fluid filled target is performed. On this Ksi representation, the multiple space A*-wave echoes cause multiple space resonances on a Ksi-cut versus k. Those numerical results are investigated using SWAM. The so-identified multiple spatial resonances correspond very well to the earliest shell whispering gallery waves families found by Veksler et al. in terms of RST.