Moving Objects

In a FLOW-3D simulation, a general moving object (GMO) is a rigid body with any kind of motion that is either user-prescribed or dynamically coupled with fluid flow. It can have six-degrees-of-freedom or motion constraints such as a fixed axis/point. Prescribed forces and torques can be applied on a GMO under coupled motion. The GMO model allows multiple rigid bodies under independent motion types as well as rigid body interactions including collisions and continuous contact. The model is robust, efficient and powerful and is the only one of its kind in commercial computational fluid dynamics software.

Gear simulation FLOW-3D
FLOW-3D simulation of a portion of an automotive differential.

Modeling Capabilities

  • 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
  • Specified time-dependent forces and torques can be applied to the objects
  • Model collisions and continuous contact between moving and moving/non-moving objects
  • Springs and ropes can be tethered on the objects
  • Porosity is allowed in the objects
  • Heat conduction and convection are allowed
  • Hydraulic, gravitational, non-inertial, spring, user-defined control forces and torques are considered for objects with coupled motion.
  • Full post-processing capabilities, including visual and numerical output

Moving Objects Simulations

Our customers have taken the application of the moving objects model far beyond how we first imaged its use. From waterwheels to shot sleeves to wave energy devices, we are ever impressed with the ways in which the model is used to solve engineering problems without having to resort to complicated meshes and intensive computing resources.