Setting Boundary Conditions

This section describes how to check the current boundary condition defaults and make adjustments where necessary.

Select the inlet node in the tree and check that the boundary condition Type shown in the Properties window is Velocity Inlet.

Open the inlet > Physics Conditions node and inspect the three objects displayed under it on the simulation tree. Ensure that the Method setting in the Properties window for each of them is as follows:

Flow Direction Specification - Boundary-Normal

Velocity Specification - Magnitude + Direction

Turbulence Specification - Intensity + Length Scale

Open the Physics Values node and check each of its property sub-nodes to confirm that the Method setting in the Properties window is Constant throughout.

Select each of the Constant nodes in turn and enter the following values for the inlet conditions in the Properties window:

Static Temperature - 298 K

Turbulence Intensity - 0.1

Turbulent Length Scale - 0.001 m

Velocity Magnitude - 2.5 m/s

Repeat the above exercise for inlet 2, which should also be defined as a Velocity Inlet. The only necessary changes to the current defaults are:

Turbulence Specification method - Intensity + Length Scale

Static Temperature value - 373 K

Turbulence Intensity value - 0.1

Turbulent Length Scale value - 0.001 m

Velocity Magnitude - 10 m/s

Check the condition on the outlet node and accept the default boundary Type (Flow-Split Outlet)

Finally, select the Default_Boundary_Region node and rename it wall. Confirm that the default boundary conditions are appropriate for this problem:

Shear Stress Specification - No-slip

Tangential Velocity Specification - None

Thermal Specification - Adiabatic

Wall Surface Specification - Smooth

The Blended Wall Function values under the Physics Values node (E, Kappa) are also acceptable.