Short-Crested Wave-Current Forces on Composite Bucket Foundation for an Offshore Wind Turbine

Piguang Wang,Xiuli Du,Mi Zhao

doi:10.1155/2019/5932742

Abstract

An analytical solution for the diffraction of short-crested incident wave with uniform current on a composite bucket foundation is derived. The influences of the uniform current on wave frequency, wave run-up, wave force, and inertia and drag coefficients on the composite bucket foundation are investigated. The numerical results indicate that the current incident angle and current velocity have significant effects on the short-crested wave run-up, wave force, and inertia and drag coefficients on the composite bucket foundation. For a fixed wave number, the wave frequency, wave run-up, wave forces, and inertia and drag coefficients obviously increase with the increase of current velocity when the relative angle between the current velocity and wave propagation direction is smaller than 90°, whereas they obviously decrease when the relative angle is larger than 90°. It also can be found that the effect of wave-current interaction on the short-crested wave increases with the increase of the total wave number and the decrease of the water depth. The short-crested wave forces will be significantly increased when the current incident angle parallels to the direction of the wave propagating. Therefore, the short-crested wave-current load should be carefully considered in the design of the composite bucket foundation for an offshore wind turbine.

Highlights

Offshore wind power is one of the most important renewable green resources in the world
Many experimental and numerical studies have been conducted on offshore wind turbines, such as the monopile [4], jacket support structure [5], tripod [6], and floating offshore wind turbines [7]
Lian et al [33] derived the analytical solution for calculating the linear plane wave force on a composite bucket foundation

Summary

Introduction

Offshore wind power is one of the most important renewable green resources in the world. The problems about short-crested wave diffraction around large-scale structures are investigated by many researchers [27,28,29]. In literature there are very few studies on the wave forces on a composite bucket foundation by using analytical, experimental, or numerical method. Lian et al [33] derived the analytical solution for calculating the linear plane wave force on a composite bucket foundation. Wang et al [34] derived the analytical solution for calculating the wave force on a composite bucket foundation subjected to short-crested waves. This study is mainly to investigate the short-crested wave-current forces around a composite bucket foundation with uniform current. An analytical solution for the diffraction of short-crested incident wave on axisymmetric structures with uniform current is derived. The results will provide a useful guide for the design of offshore wind turbines

Formulation of the Problem

The Analytical Solution of the Problem

Results and Discussion

Conclusions