With beta features enabled (as described in Introduction), you have the ability to solve the film continuity and energy equations without solving the film momentum equation (that is, with fixed film velocity). This is helpful when obtaining film solutions in applications where the wall film is formed by condensation in a static flow field.
This is controlled using the Solution Options in the Eulerian Wall Film dialog box (Model Options and Setup tab):
When the Solve Momentum option is disabled, film velocity is not solved, and the existing film velocities are fixed.
When the Solve Momentum option is enabled and the Momentum Equation option is disabled, analytical film velocity solutions apply as described in Obtaining Film Velocity Without Solving the Momentum Equations in the Fluent Theory Guide.
This is can also be controlled via the text user interface (TUI). When you enter the
define/models/eulerian-wallfilm/model-options text command, you
will be prompted to specify whether you want to solve the film equation:
define/models/eulerian-wallfilm/model-optionsSolve Film Velocity? [yes]
If you answer no, then the existing film velocities will be
fixed.
If you answer yes, then you will be prompted to specify whether
you want to solve the momentum equation:
Solve Momentum Equation? [yes]no
Answering no will apply analytical film velocity
solutions.