Generation of synthetic turbulence at LES inlets can be defined using the cs_user_les_inflow_define user function, and possibly updated using cs_user_les_inflow_update, with cs_user_les_inflow_advanced allowing for finer definition of target statistics the inlet if needed.
The cs_user_les_inflow_define function is the main entry point for LES inflow definitions.
It can be used to set general options, such as the specific checkpoint/restart behavior, as in the following example:
For each LES inlet, the cs_les_inflow_add_inlet must be used.
For example, to use the Batten Method for boundary faces of a zone named INLET_1:
And to use the Synthetic Eddy Method for boundary faces of a zone named INLET_2:
To update reference velocity, turbulent kinetic energy, or dissipation rate for a given turbulence inlet, the cs_user_les_inflow_update function may be used. It is called automatically for each LES inlet defined previously.
The following example illustrates modifying values for the example zone named INLET_1:
Mean velocity, Reynolds stresses an dissipation are deduced from a wall law for the zone named INLET_1 (no modification of the statistics of the flow is provided for the other synthetic turbulence inlets).
Reynolds stresses and dissipation at the inlet are computed using the turbulence intensity and standard laws for a circular pipe for for the zone named INLET_1 (no modification of the statistics of the flow is provided for the other synthetic turbulence inlets).