TY - GEN

T1 - An anisotropic subgrid model for large eddy simulation of wall bounded turbulent flows

AU - Badarayani, Sachin S.

AU - Squires, Kyle

PY - 2007

Y1 - 2007

N2 - Large Eddy Simulation (LES) of high-Reynolds-number wall-bounded turbulent flows is prohibitively expensive if the energy-containing eddies in the near-wall region are resolved. This motivates the use of wall-layer models in which an approximate solution of the near wall dynamics is bridged to an LES of the outer flow. The main interest of the present work are wall-modeling strategies based on Detached Eddy Simulation (DES). In these approaches, the near-wall solution is closed using a Reynolds-averaged Navier Stokes model with a subgrid closure applied to the outer flow. As is well known, the original DES formulation applied directly as a wall model results in a shift in the velocity profile, corresponding to an under-estimation of the skin friction. A new formulation is proposed in this contribution in which the wall-parallel components of the modeled stress are reduced in order to lower the influence of the model and increase the resolved stress. The effectiveness of the new model is evaluated via comparison against DES predictions using the original and recently-proposed versions of the method. The effect of grid resolution and model parameters are also assessed using computations of turbulent channel flow at a Reynolds number based on friction velocity and channel halfwidth of 5000. The predictions show that the anisotropic form of the model stress yields an improved prediction of the mean velocity profile in better agreement with the logarithmic law and with larger resolved stress in the near-wall region.

AB - Large Eddy Simulation (LES) of high-Reynolds-number wall-bounded turbulent flows is prohibitively expensive if the energy-containing eddies in the near-wall region are resolved. This motivates the use of wall-layer models in which an approximate solution of the near wall dynamics is bridged to an LES of the outer flow. The main interest of the present work are wall-modeling strategies based on Detached Eddy Simulation (DES). In these approaches, the near-wall solution is closed using a Reynolds-averaged Navier Stokes model with a subgrid closure applied to the outer flow. As is well known, the original DES formulation applied directly as a wall model results in a shift in the velocity profile, corresponding to an under-estimation of the skin friction. A new formulation is proposed in this contribution in which the wall-parallel components of the modeled stress are reduced in order to lower the influence of the model and increase the resolved stress. The effectiveness of the new model is evaluated via comparison against DES predictions using the original and recently-proposed versions of the method. The effect of grid resolution and model parameters are also assessed using computations of turbulent channel flow at a Reynolds number based on friction velocity and channel halfwidth of 5000. The predictions show that the anisotropic form of the model stress yields an improved prediction of the mean velocity profile in better agreement with the logarithmic law and with larger resolved stress in the near-wall region.

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U2 - 10.1115/FEDSM2007-37318

DO - 10.1115/FEDSM2007-37318

M3 - Conference contribution

AN - SCOPUS:40549141511

SN - 0791842886

SN - 9780791842881

T3 - 2007 Proceedings of the 5th Joint ASME/JSME Fluids Engineering Summer Conference, FEDSM 2007

SP - 1359

EP - 1366

BT - 2007 Proceedings of the 5th Joint ASME/JSME Fluids Engineering Summer Conference, FEDSM 2007

T2 - 2007 5th Joint ASME/JSME Fluids Engineering Summer Conference, FEDSM 2007

Y2 - 30 July 2007 through 2 August 2007

ER -