Scour Characteristics and Equilibrium Scour Depth Prediction around Umbrella Suction Anchor Foundation under Random Waves

Abstract

A series of numerical simulation were conducted to study the local scour around umbrella suction anchor foundation (USAF) under random waves. In this study, the validation was carried out firstly to verify the accuracy of the present model. Furthermore, the scour evolution and scour mechanism were analyzed respectively. In addition, two revised models were proposed to predict the equilibrium scour depth Seq around USAF. At last, a parametric study was carried out to study the effects of the Froude number Fr and Euler number Eu for the Seq. The results indicate that the present numerical model is accurate and reasonable for depicting the scour morphology under random waves. The revised Raaijmakers’s model shows good agreement with the simulating results of the present study when KCs,p < 8. The predicting results of the revised stochastic model are the most favorable for n = 10 when KCrms,a < 4. The higher Fr and Eu both lead to the more intensive horseshoe vortex and larger Seq.

Experimental Study of Local Scour around Tripod Foundation in Combined Collinear Waves-Current Conditions

“…From Figure 4, it can be seen that Equation ( 6) can depict the scour evolution effectively around tripod in combined waves and current. In this way, the equilibrium scour depth in following section was obtained by Equation (6).…”

“…So far, the monopiles have been widely used in offshore wind farms [1,2]. After the monopiles were installed in the seabed, due to the formation of horseshoe vortex and wake vortex in the upside and lee-side of the monopile respectively, the shear stresses on the seabed induced by waves and current were amplified in the vicinity of the monopile [3][4][5][6]. Consequently, the sediments adjacent to the monopile surface would be mobilized and carried away by shear stresses, leading to scour pits emerging.…”

Failure Behavior and Surrounding Soil Stress Responses of Suction Anchor in Low-Strength Muddy Clay

“…Yang et al [28] and Cheng et al [29] analyzed suction anchors' bearing and failure performance based on numerical methods. Hu et al [30] conducted numerical simulations to study the local scour around suction anchors. Analytical and numerical simulation methods have obtained many important results, which have greatly contributed to the design and construction technology of suction anchors.…”

Numerical simulation of unsteady flow field around monopile under the combined influence of wave and vibration

“…The resulting changes in the bed shear stress are also of great concern. The vortex structure in the flow field leads to the increase of the velocity gradient near the wall [8,9], which affects the time history of the oscillating flow with periodic changes, and leads to the occurrence of the peak shear stress [10][11][12]. The increase of shear stress caused by the horseshoe vortices are also the main driving force, leading to the scouring around the pile [13][14][15].…”