TY - GEN
T1 - A physical basis of the slip-wall model for wall-modeled large-eddy simulations
AU - Yang, Xiang I.A.
AU - Bose, Sanjeeb T.
N1 - Funding Information:
The work was funded by the US AFOSR (Grant No. 1194592-1-TAAHO). XY is grateful to C. Meneveau, A. Lozano-Duran and H. J. Bae for their helpful suggestions and fruitful discussions.
PY - 2017
Y1 - 2017
N2 - Conducting large-eddy simulations (LES) implies the use of LES filters, which are commensurate with the local grid spacing. For wall modeled LES (WMLES) where the grid spacing in the wall-normal direction scales with the local boundary layer height, the near-wall turbulence is typically not well resolved. Because of the poorly-resolved near-wall region, the no-slip condition no longer applies; and a near-wall closure (an LES wall model) must be used. Recently S. T. Bose & P. Moin (Physics of Fluids, 26, 015104, 2014, DOI: http://dx.doi.org/10.1063/1.4849535) proposed to use a Robin-type near-wall closure ui -lp∂ui/∂ y = 0, where ui's are the slip velocities at the wall, lp is a slip length and the subscript i = 1, 2, 3 indicate the streamwise, wall-normal and spanwise directions respectively. Different from most physics-based LES wall models, this slip wall model is based on the use of a differential LES filter. In the present work, we provide a physics-based interpretation for this Robin-type wall closure. We show that the model is compatible with arbitrary LES filter and it can be motivated by the same considerations that lead to the equilibrium wall model. The possibility of explicitly accounting for non-equilibrium effects is briefly discussed. The model is tested in turbulent channel flow and its performance is compared against other wall models. The flow quantities of interest here include the mean velocity, the variance of the streamwise velocity fluctuation and the instantaneous wall shear stress.
AB - Conducting large-eddy simulations (LES) implies the use of LES filters, which are commensurate with the local grid spacing. For wall modeled LES (WMLES) where the grid spacing in the wall-normal direction scales with the local boundary layer height, the near-wall turbulence is typically not well resolved. Because of the poorly-resolved near-wall region, the no-slip condition no longer applies; and a near-wall closure (an LES wall model) must be used. Recently S. T. Bose & P. Moin (Physics of Fluids, 26, 015104, 2014, DOI: http://dx.doi.org/10.1063/1.4849535) proposed to use a Robin-type near-wall closure ui -lp∂ui/∂ y = 0, where ui's are the slip velocities at the wall, lp is a slip length and the subscript i = 1, 2, 3 indicate the streamwise, wall-normal and spanwise directions respectively. Different from most physics-based LES wall models, this slip wall model is based on the use of a differential LES filter. In the present work, we provide a physics-based interpretation for this Robin-type wall closure. We show that the model is compatible with arbitrary LES filter and it can be motivated by the same considerations that lead to the equilibrium wall model. The possibility of explicitly accounting for non-equilibrium effects is briefly discussed. The model is tested in turbulent channel flow and its performance is compared against other wall models. The flow quantities of interest here include the mean velocity, the variance of the streamwise velocity fluctuation and the instantaneous wall shear stress.
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M3 - Conference contribution
AN - SCOPUS:85033231535
T3 - 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017
BT - 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017
PB - International Symposium on Turbulence and Shear Flow Phenomena, TSFP10
T2 - 10th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2017
Y2 - 6 July 2017 through 9 July 2017
ER -