Verification of a Total Lagrangian ANCF Solution Procedure for Fluid–Structure Interaction Problems

Abstract

The objective of this investigation is to verify a new total Lagrangian continuum-based fluid model that can be used to solve two- and three-dimensional fluid–structure interaction problems. Large rotations and deformations experienced by the fluid can be captured effectively using the finite element (FE) absolute nodal coordinate formulation (ANCF). ANCF elements can describe arbitrarily complex fluid shapes without imposing any restriction on the amount of rotation and deformation within the finite element, ensure continuity of the time-rate of position vector gradients at the nodal points, and lead to a constant mass matrix regardless of the magnitude of the fluid displacement. Fluid inertia forces are computed, considering the change in the fluid geometry as the result of the large displacements. In order to verify the ANCF solution, the dam-break benchmark problem is solved in the two- and three-dimensional cases. The motion of the fluid free surface is recorded before and after the impact on a vertical wall placed at the end of the dam dry deck. The results are in good agreement with those obtained by other numerical methods. The results obtained in this investigation show that the number of degrees-of-freedom (DOF) required for ANCF convergence is around one order of magnitude less than what is required by other existing methods. Limitations and advantages of the verified ANCF fluid model are discussed.