An Implicit Incompressible CFD Solver in LS-DYNA for Fluid-Structure Interaction Problems

The present work is an introduction to a new CFD solver in LS-DYNA®. This solver is part of the efforts put in LS- DYNA with the objective to expand the capabilities into new challenging problems in industry. The new CFD solver will focus on fluid-structure interaction (FSI) applications where incompressible fluids interact with the existing structures in LS-DYNA. Incompressible flows are present in a great variety of industrial applications from sloshing problems to aerodynamics at low Mach numbers. This new incompressible CFD solver coupled to LS-DYNA mechanics will provide an implicit time integration scheme allowing larger time steps and faster convergence to steady state. One of the main features of the solver is the Lagrangian representations of all FSI interfaces providing exact imposition of boundary conditions. In this way the fluid mesh and the solid mesh are tightly coupled such that the fluid domain deforms following the Lagrangian structure displacements. The rest of the domain follows an Arbitrary Lagrangian-Eulerian formulation. The image bellow shows the mesh movement and the conformity of the fluid mesh to the solid mesh.