Numerical study on the six-DOF anchoring process of gravity anchor using a new mesh update strategy

Compared with the conventional solid gravity anchor, one new type hollow anchor is designed to improve the stability and maneuverability of the gravity anchor. One water channel is dug through the center line of a traditional solid anchor to decrease the rotation angle and the drift distance when anchoring. In this study, scaled models of one traditional solid gravity anchor and one new type hollow gravity anchor are released under the water, and their anchoring processes are experimentally recorded and numerically simulated. Because the large-scale six-DOF motion of the anchor may lead to the unexpected dynamic mesh distortion, a six-DOF motion-based zonal mesh update (MBZMU) strategy is developed to control the mesh quality and guarantee the convergence and accuracy of the numerical results. As expected, simulated numerical anchoring processes of the two gravity anchor models agree well with the experimental measurements. Additionally, both the anchoring time and deviation of the hollow gravity anchor model are smaller than those of the solid anchor model during anchoring, indicating better practical and economic value of the hollow gravity anchors in engineering.