Underwater vibro-acoustics analysis of plates with sharkskin inspired surface modifications.

Abstract

This paper investigates the vibro-acoustic response of a coupled fluid-loaded rectangular isotropic plate, incorporating point masses inspired by sharkskin biomimetic surface treatment. Previous studies examined changes in plate vibro-acoustic response induced by a hydrodynamic field or point mass loading separately. The research focuses on studying sound radiation characteristics of plates undergoing multimode transverse vibrations, emphasizing submerged plates with modified sharkskin wettability. A semi-analytical model considers the coupled effect of hydrodynamic added mass and denticle mass for surface modification. The sharkskin layer model employs the Dirac delta function to represent the array pattern, where small denticle mass is applied to upper and lower plate surfaces. Evaluation of hydrodynamic added mass involves analyzing fluid kinetic energy, eliminating singularity through a polar coordinate transformation, and using Rayleigh integration for analytical evaluation of underwater sound radiation characteristics. The proposed mathematical formulation is validated by comparing frequency responses and vibro-acoustic characteristics of bare plates (in vacuo and in water) with existing literature, showing good agreement. A comparative analysis contrasts vibro-acoustic features of plates resembling sharkskin with unmodified or bare plates, extensively examining the impact of surface modification across different boundary conditions, baseplate material, and denticle spacing. The proposed analytical solutions may aid in designing underwater devices for acoustic wave manipulation.