Open AccessLarge‐eddy simulation of oscillating boundary layers: Model comparison and validation
Author(s) -
Radhakrishnan Senthilkumaran,
Piomelli Ugo
Publication year - 2008
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jc004518
Subject(s) - eddy , mechanics , law of the wall , turbulence , reynolds stress , boundary layer , logarithm , turbulence modeling , large eddy simulation , physics , boundary (topology) , momentum (technical analysis) , reynolds number , statistical physics , mathematics , mathematical analysis , finance , economics
Large‐eddy simulations of oscillating boundary layers over smooth and rough walls in the fully turbulent regime have been carried out. Several models for the unresolved subgrid‐scale (SGS) stresses are compared, as well as different approximate treatments of the wall layer, where none of the momentum‐transporting eddies is resolved. The simulations show that the use of advanced SGS models coupled with approximate boundary conditions can predict the flow successfully. Dynamic SGS eddy‐viscosity models yield more accurate results than the fixed‐coefficient one, which yields an excessively large SGS eddy viscosity, damping the wall‐normal fluctuations. The shifted logarithmic‐law approximate boundary condition, which accounts for the inclination of the near‐wall eddies, results in prediction of the wall stress within 3% of the experimental data throughout the cycle. The standard logarithmic law also gives adequate results, with a maximum error of 6%. A modification of the rough‐wall logarithmic law that accounts for transitional roughness effects was also tested; at this Reynolds number, however, this correction made little difference in the numerical results.