Along with CAVS computational engineers, Dr. Shanti Bhushan is involved in the development of advanced turbulence model for CFD simulations. The key ongoing projects include:
Algebraic LES Model
The model is derived from the deductive iteration of the subgrid scale stress transport constitutive equations. The model has an additional term over the mixed model, which accounts for an independent modeling of the backscatter. The model coefficients have been evaluated both analytically and using dynamic approach.
Isosurfaces of Q criterion showing the vortical structures predicted by DES (LEFT) and DHRL (RIGHT) for SUB-OFF
Dynamic Hybrid RANS/LES (DHRL) model
The DHRL model represents significant differences with more commonly used approaches including seamless coupling between RANS and LES regions using physics-based method based on enforcing the continuity of turbulence production, ability to couple any desired RANS model with any desired LES subgrid stress model to produce a unique hybrid model, exact recovery of RANS solution in steady-state regions of the flow, and the rapid transition in separated shear layers from RANS to LES type modeling, compared to existing methods
Identification of Large Scale Bypass Transition Onset marker
Bypass transition flow physics is one of the least understood problems in fluid mechanics, with researchers and engineers wrestling with it for decades. One of the primary hurdles in the development of physics-based models is the lack of proper understanding of the turbulence dynamics in the transition boundary layer. This research aims to improve the understanding using systematic high-fidelity DNS studies, and by focusing on TKE and stress budget analysis.
Vortical structures show the generation of Klebanoff modes in pre-transition region, and hairpin structures during transition.