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Unsteady turbulent flow with sudden pressure gradient changes
Author(s) -
Chung Yongmann M.
Publication year - 2005
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.917
Subject(s) - turbulence , pressure gradient , mechanics , k epsilon turbulence model , open channel flow , reynolds stress , vorticity , physics , vortex , k omega turbulence model , pipe flow , velocity gradient , chézy formula , turbulence kinetic energy , adverse pressure gradient , flow (mathematics) , turbulence modeling , reynolds number , shear stress
Direct numerical simulations are performed for a turbulent flow subjected to a sudden change in pressure gradient. The calculations are started from a fully developed turbulent channel flow at Re τ =180. The pressure gradient of the channel flow is then changed abruptly. The responses of the turbulence quantities (e.g. turbulence intensities, Reynolds shear stress, and vorticity fluctuations) and the near‐wall turbulence structure to the pressure gradient change are investigated. It is found that there are two different relaxations: a fast relaxation at the early stage and a slow one at the later stage. The early response of the velocity fluctuations shows an anisotropic response to the near‐wall turbulence. Copyright © 2005 John Wiley & Sons, Ltd.