Physics – Fluid Dynamics
Scientific paper
Nov 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001aps..dfd.jf015z&link_type=abstract
American Physical Society, 54th Annual Meeting of the Division of Fluid Dynamics November 18 - 20, 2001 San Diego, California Me
Physics
Fluid Dynamics
Scientific paper
We discuss large-eddy simulation (LES) near the surface of planetary boundary-layer (PBL) flows in the region where vertical velocity is under-resolved and expectation values, variance and skewness of velocity are poorly predicted. In these flows, the inertial layer extends to a "roughness height." We have found that, at the first few grid levels, predictions are sensitive to both the subfilter-scale (SFS) model, and the model for the surface SFS stress. In previous work we proposed a ``Resolvable SubFilter-Scal'' (RSFS) model (Zhou, Brasseur & Juneja, Phys. Fluids, September 2001) specifically for highly under-resolved turbulence that greatly improved predictions of the turbulence structure of homogenous anisotropic highly under-resolved turbulence, as compared with eddy viscosity and similarity subfilter-scale (SFS) models. However, in the absence of changes to the surface boundary conditions for SFS stress, the RSFS model leads to only minor improvement in prediction of expectation values. The traditional ``drag law,'' in which SFS stress is made proportional to resolved velocity at the first grid level, appears to couple too strongly surface flux with dynamics at that grid level. We therefore apply a hybrid approach, in which Reynolds averaged Navier-Stokes (RANS) is solved with a RANS eddy viscosity closure on a highly elongated grid between the surface and first grid level. In this way, the LES locally forces the RANS calculation through its upper boundary, while the RANS calculation generates the surface fluxes for the LES. The consequences of this approach will be compared with the standard boundary condition.
Brasseur James
Zhou Yong
No associations
LandOfFree
Large-eddy simulation in the near-surface region of planetary does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Large-eddy simulation in the near-surface region of planetary, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Large-eddy simulation in the near-surface region of planetary will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1235234