Study of the Reduction of Vertical Oscillations of a Floating Structure

Abstract The main objective of this work is to investigate an innovative floating structure by introducing the action of an air chamber as a compartment of the floater’s hull, as an initial study to improve its heave motion behavior in waves. A mathematical modeling for the air chamber influence on the floating structure motion is presented and the fundamentals of the dynamic of the motion of the floating structure is studied with the aid of a simplified model geometry. A small physical model was used for experiments conducted in a calm water tank. In order to conduct the analysis of the dynamics, a numerical routine was developed to solve the vertical equation of motion of the structure based on simplified formulations to address external oscillatory vertical forces. As a preliminary result, it is observed that the presence of the air chamber may reduce the floating structure vertical motion. The effect of the air chamber on the natural frequency of oscillations could be verified experimentally. The results of the numerical simulations were compared with the laboratory experiments, showing that this simple numerical model is a useful computational tool to support practical development of the low heave floating structure concept. This study constitutes the first step towards mastering the design and operation of a real floating platform, with potential to be applied to floating structures bearing wind turbine towers for power generation installations on high seas, and to other deep waters operations such as oil and gas production or subsea mining.