TY - GEN
T1 - A coarse-grained LES model for turbulent channel flow
AU - Hu, N.
AU - Liu, H.
AU - She, Z. S.
AU - Hussain, F.
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011
Y1 - 2011
N2 - A hybrid RANS-LES method based on structural ensemble dynamics (SED) theory is presented, wherein coarse-grained turbulent fluctuation amplitudes are re-normalized using instantaneous values of an order function, i.e. mixing length, in the ensemble-averaged Navier-Stokes (EANS) equation. The re-normalization procedure is applied throughout the channel (at wall friction Reynolds numbers Reτ=1 050 and 2 000), to evade the common problem of log-layer mismatch. The mean and rms velocity profiles show improved agreement with DNS at very coarse grids (40×49×20 for both Re's). The method dissipates turbulent kinetic energy in the bulk flow, and increases turbulent fluctuations in the buffer region, mimicking the physical forcing of the sub-grid scale term. The results demonstrate the feasibility to reconstruct the unsteady effect of wall-bounded flows constrained by order functions.
AB - A hybrid RANS-LES method based on structural ensemble dynamics (SED) theory is presented, wherein coarse-grained turbulent fluctuation amplitudes are re-normalized using instantaneous values of an order function, i.e. mixing length, in the ensemble-averaged Navier-Stokes (EANS) equation. The re-normalization procedure is applied throughout the channel (at wall friction Reynolds numbers Reτ=1 050 and 2 000), to evade the common problem of log-layer mismatch. The mean and rms velocity profiles show improved agreement with DNS at very coarse grids (40×49×20 for both Re's). The method dissipates turbulent kinetic energy in the bulk flow, and increases turbulent fluctuations in the buffer region, mimicking the physical forcing of the sub-grid scale term. The results demonstrate the feasibility to reconstruct the unsteady effect of wall-bounded flows constrained by order functions.
KW - channel
KW - hybrid RANS/LES method
KW - large eddy simulation
KW - order functions
KW - structural ensemble dynamics
UR - http://www.scopus.com/inward/record.url?scp=80355136388&partnerID=8YFLogxK
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U2 - 10.1063/1.3651835
DO - 10.1063/1.3651835
M3 - Conference contribution
AN - SCOPUS:80355136388
SN - 9780735409361
T3 - AIP Conference Proceedings
SP - 61
EP - 65
BT - Recent Progresses in Fluid Dynamics Research - Proceedings of the Sixth International Conference on Fluid Mechanics, ICFM VI
T2 - Proceedings of the 6th International Conference on Fluid Mechanics: Recent Progresses in Fluid Dynamics Research, ICFM VI
Y2 - 30 June 2011 through 3 July 2011
ER -