The Moving Wall (Wall Functions) boundary condition applies wall functions to a wall in a turbulent flow with prescribed velocity uw. Enter the component values or expressions in the Velocity of moving wall fields (SI unit: m/s).

C O N S T R A I N T S E T T I N G S

To display this section, click the Show button () and select Advanced Physics Interface Options. Select a Constraint type—Bidirectional, symmetric or Unidirectional for the following wall boundary conditions: No slip, Moving wall, and Leaking wall. The other types of wall boundary conditions with constraints use unidirectional constraints only. Select the Use weak constraints check box (available for all boundary conditions except Sliding wall, which does not add any constraints) to use weak constraints and create dependent variables for the corresponding Lagrange multipliers.

Interior Wall

The Interior Wall boundary condition includes a set of boundary conditions describing the fluid flow condition at an internal wall.

It is similar to the Wall boundary condition available on exterior boundaries except that it applies on both sides of an internal boundary. It allows discontinuities (velocity, pressure, turbulence) across the boundary.

The Interior Wall boundary condition is only available for single phase

flow. It is compatible with laminar and turbulent flows.

Note

B O U N D A R Y S E L E C T I O N

From the Selection list, choose the boundaries that represent interior walls.

B O U N D A R Y C O N D I T I O N

Select a Boundary condition—No slip (the default), Slip, or Moving wall.

No Slip

No slip is the default boundary condition for a stationary solid wall. The condition prescribes u = 0 on both sides of the boundary, that is, that the fluid at the wall is not moving.

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