Setting up a 2D DFBI Simulation

Some DFBI applications can be modeled in 2D, providing a more computationally-efficient solution compared with simulating in full 3D coordinates. One such example—One-DOF Rotating Motion for 2D set-ups—was introduced in Simcenter STAR-CCM+ 12.04 to simulate rotating electric machines. There are now three additional 2D motions available—including one for axisymmetric set-ups.

Simcenter STAR-CCM+ allows you to create a 2D 6-DOF body, upon which you may apply a 2D DFBI motion and external forces—for example, via fluid interaction or associated couplings (see Creating a 6-DOF Body and Coupling DFBI Bodies for more information). The options and workflow for 2D body motion is very similar to that of 3D DFBI—the key differences relating to the constraints imposed by the coordinate systems used.

You can choose from four options for 2D body motion options:

To set up a 2D DFBI simulation:
  1. Right-click the DFBI > 6-DOF Bodies > New Body > 2D node and select the body type:
    • Continuum Body
    • Mechanical Body
    The properties and options available depend on the body type selected. The motion of the DFBI body owing to forces and moments exerted by the physics can only be simulated by the continuum body. A mechanical body has no volume mesh associated with it and can only respond to gravity forces, or any additional external forces or body couplings that you define.
  2. For a Continuum Body, select the [Body 2D 1] node and set the appropriate properties to define the body type and its related motion:
    1. Select the boundaries that comprise the Body Surface.
      NoteYou must not mix 2D and 3D boundaries within the same body surface. For a 2D body, all boundaries must be 2D; for a 2D body with axisymmetric motion, all boundaries must be axisymmetric.
    2. Provide the Body Mass of the 2D body.
    3. Set the Body Motion Option.
  3. For a Mechanical Body, select the geometry parts that comprise the Body Parts; for example, this can be used for the visualization of a mechanical body within a DFBI displayer (see Setting up DFBI Post-Processing).
  4. Select the Body Motion Option node under the DFBI > 6-DOF Bodies > [Body 2D 1] node and specify the properties for the 2D DFBI motion.
    In all 2D body motion cases, the z-coordinate is not relevant. Whenever a z-coordinate must be specified, set it to zero.
    For more information on the properties, see 2D Body Motion Options.
  5. To define initial values such as Angular Velocity, Center of Mass, Moment of Inertia, and Orientation, expand the Initial Values node, select the sub-nodes in turn, and set their properties. For more details, refer to Initial Values Reference.
    NoteThe units of all values are effectively per unit length of the body in z-direction, for 2D simulations, and per radian, for axisymmetric simulations. For a full description of properties, see What are Initial Values.