-
From the Boundaries section of the action bar, click Wall
.
- Optional:
Enter a descriptive
Name.
-
Select a boundary surface of a fluid domain as the geometry support for the
wall.
-
Specify the fluid or solid Physics behavior that
applies for this wall boundary.
-
Choose the Wall type.
Wall type | Description |
---|
No-Slip |
The fluid sticks to the wall with no relative velocity between the
fluid and the surface. Use this wall type where viscous effects are
significant. |
Slip |
The 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. |
Moving Wall |
Simulates a wall moving in a linear fashion that imparts velocity to
the fluid in contact with it. You could use a moving wall to simulate
the effect of a piston that moves gas out of a chamber. |
Rotating Wall |
Simulates a wall that rotates about an axis and imparts velocity to
the fluid in contact with it. You could use a rotating wall to simulate
the effects of a fan blade. |
- Optional:
For a moving wall, specify the motion in space in all three axes and in your
selected coordinate system.
For more information, see Defining Motion for a Moving Wall.
- Optional:
For a rotating wall, specify the axis of rotation and the rotational speed.
For more information, see Defining Rotational Behavior for a Rotating Wall.
-
Specify a Thermal condition to describe the heat
exchange behavior between the wall and the fluid.
Note:
Thermal condition options are available only if you enable thermal effects
in the fluid physics of the simulation.
Option | Description |
---|
Adiabatic |
No heat exchanged between the wall and the fluid. |
Temperature |
No heat exchanged, but the wall surface is held at a constant
temperature. |
Heat flux |
Heat exchanged at a specified flux rate. |
Film condition |
Heat exchange from convection between the wall and the fluid. Two
parameters determine the level of heat flux:
- Film coefficient, a constant that relates heat flux to the
difference in temperature between the wall and the fluid
- Far-field temperature, which is the temperature of the
surrounding fluid
The default values are appropriate for typical objects at room
temperature. |
Radiation to ambient |
Heat radiation from the wall to the environment. The emissivity of
the wall (that is, its ability to transmit thermal energy) and the
ambient temperature determine the level of radiation. |
- 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:
-
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.
-
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.
- Optional:
If you are creating a multispecies flow simulation, expand the
Multispecies Conditions options and then see Defining the Multispecies Conditions at a Wall.
- Optional:
Specify the surface-to-surface radiation behavior of the wall.
For more information, see Defining Surface-to-surface Radiation Behavior at a Wall.
- Optional:
Specify the solar radiation behavior for the wall.
For more information, see Defining Solar Radiation Behavior at a Wall.
-
Click OK.
|