Frequency spectra of free flooded ring transducers

The resonant modes of free-flooded ring or cylindrical transducers are studied as a function of aspect ratio and their frequency spectra are determined using finite element analysis. Dependence of resonant frequencies corresponding to various modes of vibrations on its geometry is studied quantitatively. Modes corresponding to mechanical resonances are identified using in-air analysis. Additional modes corresponding to cavity resonance observed in underwater analysis are attributed to acoustic interaction between the encased volume and the surrounding medium. Presence of strong mode-coupling is observed for intermediate aspect ratio. FEM results are compared with the analytical model results. Importance of selecting appropriate values of length-to-diameter (L/D) ratio of free-flooded cylindrical transducers is discussed and optimized values are recommended for applications that require broadband transducer characteristics.