Noninertial Frame

Noninertial Frame is a volume condition in the Flow module pertaining to selected Volumes. Specify the Noninertial Frame (see Figure 5.18) as follows:

Geometric Entities Panel > Volumes > [Desired Volume]
Properties Panel > Model Tab > Flow > Noninertial Frame

Noninertial Frame is used to solve flow in moving reference frames. It solves the pressure and flow field in a rotating or linearly accelerating reference frame for the selected volume. When solving in the noninertial frame, the rotational boundary conditions are set in terms of the stationary (laboratory) reference frame. However, the pressure and flow field are still displayed in terms of the non-rotating (laboratory) reference frame. Volumes with a Noninertial Frame and volumes with stationary frame are solved together using Multiple Reference Frames (MRF). These volumes are connected using the Mismatched Grid Interfaces (MGI) algorithm.

The Noninertial Frame is defined using the options:

Rotational Direction, Rotational Speed, Rotational Center, and Rotational Axis Vector
Velocity: Allows simulation of a linearly accelerating system. When the volume is specified as a Noninertial Frame with a velocity, the flow field is solved in the reference frame of the accelerating coordinate system. Velocity refers to the linear velocity only. It does not refer to any change in magnitude or direction of the rotating system. The velocity is specified in terms of the components or through expressions (e.g. as a function of time).

Figure 5.23 - Noninertial Frame