There are two distinct categories of FSI:
One-way interactions, in which the fluid will impart some action on the structure, but the response of the structure does little affect the fluid motion, and Two-way interactions, where the fluid motion and pressure affects the displacement and deformation of the structure and, in turn, the structure has a significant effect on the fluid flow. An example of One-way interactions would be where a fluid heats or cools a stiff, supported structure which produces thermals tress loads and deformations in the solid, while an example of Two-way interactions, the solid structure responds to pressure or viscous shear traction in the fluid, while the fluid responds, especially from the velocity of the structure.
STAR-CCM+ uses implicit coupling to handle FSI cases, as well as Dynamic Mesh Evolution techniques such as Rigid Body Motion and Mesh Morphing techniques. FSI handled entirely in STAR-CCM+ without the need of any external software or modules, and can be controlled via Java macros to map and export fluid dynamic loads for use in a structural solver, such as our partner software ABAQUS.