Defining a Wall

You can define a wall to describe the physical behavior at the boundary surface between the fluid and solid.

  1. From the Conditions section of the Flow analysis assistant panel, expand Walls and click Wall condition .
  2. Optional: Enter a descriptive name.
  3. Select the geometry supports in the model.

    A wall feature must be applied to a boundary surface of a fluid domain.

  4. Choose the Wall type.
    Wall typeDescription
    No-SlipThe fluid sticks to the wall with no relative velocity between the fluid and the surface. Use this wall type where viscous effects are significant.
    SlipThe fluid does not stick to the wall. Use this wall type where viscous effects are negligible or when the mesh size at the wall is much larger than the boundary layer thickness. Slip walls are also appropriate for models with symmetry surfaces and zero shear.
  5. Optional: Select Enable wall roughness to include the effects of wall roughness and the resulting turbulent flow in the simulation. You can then adjust either or both of the following aspects of wall roughness:
    1. Adjust the average Roughness height of the components on the wall that contribute to its roughness. For example, this parameter might specify the average height of the individual grains of sand on a piece of sandpaper.
    2. Adjust the Roughness constant, a measure of the uniformity of roughness. Values range from 0 to 1, with higher values indicating less uniformity. A value of 0.5 represents a tightly packed, uniformly distributed roughness.