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Simulating Fluid Structure Interaction

FLOW-3D has extensive modeling capabilities for the fully coupled interaction of fluid and solids, from the General Moving Objects (GMO) model for 6 DoF motion of rigid bodies to an FE-based structural analysis (FEA) of the stresses and deformations induced in solid bodies by external fluid pressure and internal thermal gradients. The latter model includes the modeling of stresses in solidifying metals as they cool to the surrounding mold and air.

The GMO model uses a fixed grid approach, where the geometric coefficients of the FAVOR™ method are updated as a body moves through the domain. The FEA model combines the fixed finite volume (FV) grid which carries the fluid solution, with the Lagrangian body-fitted finite-element(FE) mesh which is used to compute the evolution of stress in the solid (and solidified) regions of the domain. Both solutions are then coupled at the interface between the FV and FE computational domains.

Fluid Structure Interaction Model

Magnified deformations (400 times) in a steel vessel containing
an explosion using the fluid structure interaction model.

The fluid structure interaction model describes fully-coupled interaction between fluid and solid using a finite element approach to model stresses and deformations in solid components in response to pressure forces from the surrounding fluid, thermal gradients, and specified constraints. Currently, the model is limited to small deformations. Possible applications of the FSI model include:


Thermal Stress Evolution Model

Stresses in a v6 engine block are simulated with
FLOW-3D's thermal stress evolution model.

The thermal stress evolution model describes the evolution of stresses and deformations in metal during cooling. Stresses are simultaneously computed in the mold and in solidifying metal with simple options for the interaction between them. Applications of the thermal stress model include:


General Moving Objects Model

This simulation depicts the flow of water through a pipe,
causing a valve to open. The valve's motion is about a fixed axis.
FLOW-3D's general moving objects model, also known as the GMO model, is the only one of its kind in commercial computational fluid dynamics software. The model allows users to model rigid body dynamics with six-degrees-of-freedom (6 DOF) fully coupled with fluid flow. Learn more about simulating non-deformable fluid structure interactions with the GMO model.

Industry Examples

Specific uses of FLOW-3D's GMO model for various industries can be found in the application pages of the website.