Coherent Structures in Turbulent Flow over Arrays of Cubical Obstacles
The organised motion in turbulent flows over arrays of cubical obstacles has been investigated using direct numerical simulations. Six plan densities have been examined in detail. Relative to a smooth surface, the streamwise extent of the near-wall structures is decreased while their spanwise and wall normal extent is increased. Near the crests’ plane, the inclination of the average structure is larger than that over a smooth wall. The Reynolds stress anisotropy tensor and its invariants show a closer approach to isotropy over the rough wall than over a smooth wall. The mechanism leading to increased isotropy has been explained in the paper through consideration of the Reynolds stress budgets.
KeywordsDirect Numerical Simulation Reynolds Stress Spanwise Direction Turbulent Transport Smooth Wall
This research was supported in part by the National Science Foundation through TeraGrid resources provided by TACC and in part by the UK Turbulence Consortium during SL’s visits to Southampton.
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