FEM ConstraintInitialFlowVelocity

From FreeCAD Documentation

FEM ConstraintInitialFlowVelocity

Menu location
Model → Fluid boundary conditions → Initial flow velocity condition
Default shortcut
Introduced in version
See also
Constraint flow velocity, Constraint initial pressure


Creates an initial flow velocity condition for a fluid flow analysis.


  1. Press the Initial flow velocity condition button or select the menu Model → Fluid boundary conditions → Initial flow velocity condition.
  2. Enter an initial flow velocity value for the analysis. The value is entered as a combination of the 3 main cartesian vectors components (X,Y,Z).
  3. For a 3D analysis, select a 'solid' (body) from your model, for a 2D analysis select a face. However, it is also possible to select a face (e.g. the inlet of a pipe) in 3D or an edge in 2D.


For a description how to input formulas, see section Formulas in the page for the Flow velocity constraint.


In simple analyses, it is not necessary to specify the initial flow velocity, however it is recommended as best practice.