Session: 12-02-02 Wave-Structure Interactions II

Paper Number: 128085

128085 - Analysis of Higher Harmonic Loads on a Fixed Truncated Vertical Cylinder 

Understanding the characteristics of the nonlinear extreme wave loading has economic benefits for the design of offshore structures. This paper investigates the higher-harmonic loads of extreme waves on a fixed truncated vertical circular cylinder under the action of nonlinear focused waves which is correlated to the excitation force on the foundation of the cylindrical floating wind turbines. In order to analyse the higher-harmonic loads, wave groups are generated from a wave spectrum by a fully nonlinear potential flow model based on the assumption of a “Stokes-type” nonlinear harmonic structure. A general phase-based harmonic decomposition method is employed for the hydrodynamic loading on a fixed structure in water waves of moderate steepness. The local wave elevations around the structure are also visualized and compared with the pure wave elevations for the first three harmonics in order to reveal the local dynamic driving components within the wave force time-history. The results show that the higher harmonic loads follow the nonlinear harmonic structure of the Stokes-expansion type by adding a force relative phase shift coefficient. Accordingly, higher harmonic loads of a focused wave group on the truncated vertical circular cylinder can be estimated by a simple mathematical model with the linear component. Additionally, results from the simple estimation model  are compared with both the experimental data and the analytical solutions to validate the accuracy.

Presenting Author: Junru Chen Southern University of Sciencen and Technology

Presenting Author Biography: Junru Chen is PhD student at the Souhtern University of Science and Technology in Shenzhen China.

Authors:

Junru Chen Southern University of Sciencen and Technology
Xingya Feng Southern University of Science and Technology
Ye Li Southern University of Science and Technology