
Modeling Fluid Structure Interaction with FLOW-3D
General Moving Objects Model
It’s no accident that with FLOW-3D, users can model collision between objects with the General Moving Object (GMO) model. Modeling fluid structure interactions can include debris flows, opening and closing valves, counter-meshing gears, and big-particle collision. This robust model, the only one of its kind in commercial computational fluid dynamics software, allows users to model rigid body dynamics with six-degrees-of-freedom (6 DOF) fully coupled with fluid flow.
Contact Flow Science to find out how your CFD simulations can be handled with FLOW-3D's GMO model!

Fluid structure interaction of a prescribed motion in a gear simulation.
Related links:
Watch the FLOW-3D Demo
Fluid Structure Interaction Model
Springs & Ropes and Sinusoidal Motion
Adding Collision Modeling to FLOW-3D
Development Focus: Extending GMO
Three-Dimensional Collision Modeling for Rigid Bodies and Its Coupling with Fluid Flow Computation
A Fixed-Mesh Method for General Moving Objects
Fluid Structure Interaction Capabilities in FLOW-3D
- Allows up to 500 moving objects, each of which can possess 6 DoF, or rotate about a fixed axis or a fixed point. Other motion constraint patterns are also possible.
- Objects can be fully coupled with fluid flow or the user can prescribe their motion
- Objects can be made of several materials characterized by their density
- There is no restriction on complexities of geometry and motion for objects
- Model collisions and continuous contact between moving and moving/non-moving objects
- Specified time-dependent forces and torques can be applied to the objects
- Hydraulic, gravitational, non-inertial and control forces and torques can be calculated
- Full post-processing capabilities, including visual and numerical output
This FLOW-3D maritime simulation demonstrates nautical
inconvenience of a ship aground on the rocks losing fuel from
her tanks. CFD results post-processed by EnSight.
Modeling courtesy of XC Engineering.
What is a General Moving Object (GMO)?
A GMO is a rigid body in a FLOW-3D simulation that is intended to move or be moved by fluid. GMOs can have any type of user-prescribed motion, or the GMO can be dynamically coupled with the fluid flow.
Fluid Structure Interaction Simulation Examples
Several fluid structure interaction animations using the GMO model, with and without collision, are displayed on the Fluid Structure Interaction Examples page. You can also view more fluid structure interaction simulations on the FLOW-3D Fun Page.