Experimental and numerical investigation on the impact of MS2AF on local scour protection performance

Abstract

Suction anchor foundations are widely used in the offshore wind power industry. The installation of suction caissons alters the near-bed flow field and leads to local scour. This study proposes a novel integrated design for the scour protection of suction anchor foundations, known as the multihole sector suction anchor foundation (MS2AF). Through indoor flume experiments and numerical flume simulations, the local scour protection performances of MS2AFs with different design parameters under the action of steady flow were investigated. The results showed that the scour evolution of MS2AFs can be divided into three stages: slow scour, rapid scour, and scour equilibrium. The MS2AF reduced the flow shear stress on the sediment bed, thereby decreasing the depth and range of the local scour. The maximum scour depth, width, and length of the scour hole exhibited negative linear relationships with the width and thickness of the sector and decreasing-then-increasing relationships with the diameter and area ratio of the holes. Among these factors, the sector's thickness had the most significant impact. There existed an optimal diameter and area ratio that maximized the stratification effect and deceleration effect of the multihole sector.