Setting Boundary Conditions and Values

Training Guide > Rotating System Tutorials > Moving Reference Frames Tutorial > Setting Boundary Conditions and Values

Setting Boundary Conditions and Values

The fluid velocity at the inlet and the rotation conditions at the wall boundaries are specified as follows:

Select the Fluid > Boundaries > Inlet > Physics Values > Velocity Magnitude > Constant node

In the Properties window, enter a Value of 5.0 m/s

STAR-CCM+'s default rotation setting for all wall boundaries is for them to remain stationary relative to the mesh. Therefore, in absolute terms, the default setting for the wall boundaries of the Fluid region is zero rotation whilst that for the wall boundaries of the Rotating region is 2000 rpm. This is inappropriate for one wall boundary in each region: the Axis boundary in the Fluid region, which should be rotating, and the Walls boundary in the Rotating region, which should be stationary (see the Visualizing the Geometry section for their location in the problem geometry).

We will start with the conditions on the Axis boundary in the Fluid region:

Select the Axis > Physics Conditions > Tangential Velocity Specification node

In the Properties window, change the Method property to Rotation Rate

Select the Physics Values > Wall Rotation > Constant node

In the Properties window, enter 2000 rpm for the Value property (make sure you enter the units correctly)

To make the Walls boundary of the Rotating region stationary:

Select the Rotating > Walls > Physics Conditions > Tangential Velocity Specification node

In the Properties window, change the Reference Frame property to Absolute

This completes the specification of boundary conditions.

Save the simulation

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