 
Summary: A resolvable subfilterscale model specific to largeeddy simulation
of underresolved turbulence
Yong Zhou, James G. Brasseur,a)
and Anurag Junejab)
Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park,
Pennsylvania 16802
Received 20 February 2001; accepted 6 June 2001
Largeeddy simulation LES of boundarylayer flows has serious deficiencies near the surface when
a viscous sublayer either does not exist rough walls or is not practical to resolve high Reynolds
numbers . In previous work, we have shown that the nearsurface errors arise from the poor
performance of algebraic subfilterscale SFS models at the first several grid levels, where integral
scales are necessarily underresolved and the turbulence is highly anisotropic. In underresolved
turbulence, eddy viscosity and similarity SFS models create a spurious feedback loop between
predicted resolvedscale RS velocity and modeled SFS acceleration, and are unable to
simultaneously capture SFS acceleration and RSSFS energy flux. To break the spurious coupling
in a dynamically meaningful manner, we introduce a new modeling strategy in which the
gridresolved subfilter velocity is estimated from a separate dynamical equation containing the
essential inertial interactions between SFS and RS velocity. This resolved SFS RSFS velocity is
then used as a surrogate for the complete SFS velocity in the SFS stress tensor. We test the RSFS
model by comparing LES of highly underresolved anisotropic buoyancygenerated homogeneous
