Description

This LS-DYNA simulation shows a simple FSI coupling problem using strong FSI. Indeed, the density of the solid and the fluid are very close. Such cases are by definition unstable when using explicit coupling between solid mechanics and a CFD code ('added mass effect'). The user is encouraged to try this problem using the explicit DYNA solver to see the instabilities. In order to reduce those instabilities, strong fluid structure interaction is needed. In order for this to be possible, both solvers need to advance at the same time and have the same timestep thus making the use of the implicit solver for solids mandatory. If the user gives different timesteps for the solid and the fluid, the smallest one of the two will be used.