Hydrodynamic characteristics of dual-layered thin-walled concentric segmented structures

Abstract

Segmented arc structures are commonly used in marine engineering but are often vulnerable to wave penetration through their gaps. This study examines the feasibility of adding a low-cost, small breakwater behind a segmented structure to mitigate this issue effectively. An analytical model based on linear potential theory is developed to understand water wave interactions with a cylindrical and segmented arc-shaped dual-layered thin-walled structure. Using eigenfunction matching and separation of variables, the unknown function is expanded within a Chebyshev polynomial framework. With comprehensive boundary condition considerations, the integral equation is transformed into a series of algebraic equations, which are solved to determine the unknown function. Model accuracy is verified by simplifying the model and comparing it with published results. The hydrodynamic response, including wave forces and free surface elevation, is analyzed. Numerical results indicate that a small porous breakwater effectively reduces wave load on the inner cylinder and smooths wave heights within the structure and at the openings, facilitating safe ship passage and operation. This study provides practical guidance and valuable reference for engineering applications.