Fluid Tab

Boundary conditions relating to fluid are set on this tab.

It is in the [Edit Boundary Condition] dialog box. See [How to Set Boundary Condition].

There are two ways to define the fluidity to the model.

Specify the flow velocities at either the input openings or the output openings and specify the nil velocity potential to the other remaining openings.
Specify the reasonable velocity potentials to both the input and output openings.

You may enter the flow velocities to both openings, but that is not recommendable as the calculation is likely

to be inaccurate.

Femtet supports only the cases where the openings are perpendicular to the flow vectors.
If not perpendicular, the results might not be accurate.

Setting Items	Notes
Flow Velocity	Sets the fluid velocity on the face topology or the edge topology for the 2D. The flow vector is required to be perpendicular to the face or the edge. Enter the positive value for the outward flow and the negative value for the inward flow. This is primarily for the input or output openings.
Velocity Potential	Sets the fluid velocity on the face topology or the edge topology for the 2D. This is primarily for the input or output openings. If the flow velocity is set on the input opening, the fluid potential should be selected and set to nil on the output opening. The face or edge topology is required to be perpendicular to the flow vector. You may set the velocity potential on the non-perpendicular face, but the results might not be accurate. Boundary condition for the non-perpendicular face is not available in Femtet.
Wall Face	The specified face is treated as a wall face.