On the dynamic computation of the model constant in delayed detached eddy simulation

Abstract

The current work puts forth an implementation of a dynamic procedure to locally compute the value of the model constant CDES , as used in the eddy simulation branch of Delayed Detached Eddy Simulation (DDES). Former DDES formulations [P. R. Spalart et al., "A new version of detached-eddy simulation, resistant to ambiguous grid densities," Theor. Comput. Fluid Dyn. 20, 181 (2006) The current work puts forth an implementation of a dynamic procedure to locally compute the value of the model constant C DES , as used in the eddy simulation branch of Delayed Detached Eddy Simulation (DDES

Passive Scalar Transport Modeling for Hybrid RANS/LES Simulation

“…The usual log-layer mismatch, that occurs in DDES (Spalart et al, 2006), is due to depletion of the total stress when switching from RANS to eddy resolving simulation. It is alleviated in the IDDES formulation (Shur et al, 2008) and the 2 −ω formulation (Yin et al, 2015;Reddy et al, 2014). In order to avoid log-layer mismatch in passive scalar transport modeling, a smooth transition from modeled stress to resolved stress is required.…”

“…The adaptive-DDES formulation of Yin et al (2015) is summarized here. The shielding function for Delayed Detached Eddy Simulation (Spalart et al, 2006) is adopted:…”

“…The method is to devise a turbulent Prandtl number that adapts to the needs of either RANS or eddy-resolved simulation, as is required by DES. Adaptation is introduced by a modified version of the dynamic procedure of Large Eddy Simulation (LES), similarly to Yin et al (2015).…”

“…The DES portion of the present paper is an extension of that model. In Yin et al (2015), the eddy viscosity is written as 2 ω, where ω is found from the k − ω model. The length scale, is a standard DES formulation; although it differs from previous DES methods by invoking the Germano identity to compute the model constant, C DES , dynamically.…”

“…The formulation proves to be especially effective on coarse grids, as occur in DES. After testing it in a wall resolved LES, the present formulation is applied to the Adaptive DDES model of Yin et al (2015). It is validated by turbulent channel flow and turbulent boundary layer computations.…”