Potential Hydroelastic Instability of Profiled Underwater Structures

Abstract

Appendages on underwater vehicles are often given a cross-sectional profile that will produce low drag. The potential danger is that if the profile shape is not selected carefully, the structural integrity of the appendage may be endangered by hydroelastic instability. While static divergence is usually investigated, the potential for divergent oscillations leading to destructive amplitudes is not recognized as readily. Structural damping, which often is a saving feature for wind-induced loads, plays a completely insignificant role in a high-density fluid such as water. The unsteady hydrodynamic characteristics leading to self-excited oscillations are derived analytically and the means by which the dynamic instability can be minimized or eliminated are described.