Shielded Detached Eddy Simulation (SDES) is a hybrid RANS-LES turbulence model family. Starting from the DDES-SST model (see DES with the BSL or SST k-ω Model for details), it provides substantial improvements:
a shielding function that protects the RANS wall boundary layer region against influences from the LES model
improved definition of the grid length scale, for faster “transition” from RANS to LES in separating shear layers
The improved shielding function offers nearly perfect boundary layer shielding against a premature switch to the LES model. Such premature switching could otherwise cause strong deterioration of the RANS capabilities of the model in attached boundary layers [622].
Note: No special calibration has been performed for the combination of SDES with Transition SST and the Intermittency Transition model.
Note that the activation of the LES term in the freestream in any hybrid RANS-LES model can affect the decay of the freestream turbulence, which in turn affects the transition location.
For an example demonstrating the effects of the SDES model, see SDES and SBES Example.