Once the geometry of the control domain is defined, we have to proceed with setting the boundary conditions of the problem. The only conditions to be applied in this example are the Velocity Field (surface) and Pressure Field (surface) conditions.
The Velocity
Field condition is used to fix the velocity in a surface to the field given
in the Fluid window (see below). The Velocity Field can be a
general function and thus this condition can be used to specify a
It is also possible to fix the velocity (during all the simulation process) to the initial value of the function given in the corresponding Fluid window option. To do this, the corresponding Fix_Initial flag has to be marked.
For this example this condition is going to be assigned to the inlet, lateral and bottom surfaces of the control volume.
The options to be selected for the inflow surface are marked with “x” in the following list:
Fix Initial X | x |
Fix Initial Y | x |
Fix Initial Z | x |
Fix Field X | - |
Fix Field Y | - |
Fix Field Z | - |
The options to be selected for the lateral surface are marked with “x” in the following list:
Fix Initial X | - |
Fix Initial Y | x |
Fix Initial Z | - |
Fix Field X | - |
Fix Field Y | - |
Fix Field Z | - |
The options to be selected for the bottom surface are marked with “x” in the following list:
Fix Initial X | - |
Fix Initial Y | - |
Fix Initial Z | x |
Fix Field X | - |
Fix Field Y | - |
Fix Field Z | - |
Here we will apply the Pressure Field condition to the inlet and outlet surfaces of the domain. To these surfaces we will mark the Fix_Initial field. By doing this, pressure will be fixed to the initial value of the function given in the corresponding Fluid window option.
The following is a summary of applied conditions (see Figure 51).
Velocity Field | Surface 2 | |
Fix Initial X | x | |
Fix Initial Y | x | |
Fix Initial Z | x | |
Velocity Field | Surface 1 | |
Fix Initial X | - | |
Fix Initial Y | x | |
Fix Initial Z | - | |
Velocity Field | Surface 6 | |
Fix Initial X | - | |
Fix Initial Y | . | |
Fix Initial Z | x | |
Pressure Field | Surface 2 and 4 | |
Fix Initial | x |
Figure 51. Overview of the applied conditions |
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