Numerical Investigation on the Motion Dynamics of Submerged Gravity Anchors Exposed to Wave Action

Abstract

This paper presents a numerical modeling approach to analyze the dynamic response of gravity anchors subjected to waves at various submergence depths. The aim is to model stages of lowering during the installation process of offshore wind energy installations. The study includes an investigation of the effect of different outer shapes of the gravity anchor to understand the influence on the dynamic response of the anchor. The results demonstrate that the submergence depth has a significant impact on the stability of the anchor during the lowering process, particularly at the initial lowering phase, resulting in higher wave-induced forces and increased risks of instability. With the use of streamlined anchor shapes, compared with the results for the baseline anchor, a reduction of 20.9% and 16.6% in heave, 47.8% and 45.8% in pitch, and 73.4% and 75.3% in surge motions are observed for C- and V-shaped anchors, respectively. When comparing the influence of different wave parameters, compared with the wave height, the wavelength is shown to drive undesirable anchor dynamic motions.