The organised motion in a turbulent channel flow with a succession of square bars on the bottom wall has been investigated using direct numerical simulations. Several values of the ratio w/k, where k is the bar height and w is the longitudinal separation between consecutive bars have been examined in detail. Relative to a smooth surface, the streamwise extent of the near-wall structures is decreased while their spanwise extent is increased. As w/k increases, the coherence decreases in the streamwise direction having a minimum for w/k = 7. This is due to the outward motion occurring, most of all, near the leading edge of the elements. The Reynolds stress anisotropy tensor and its invariants show a closer approach to isotropy over the rough wall than over a smooth wall.
Structure of turbulent channel flow with square bars on one wall / Leonardi, S.; Djenidi, L.; Orlandi, Paolo; Antonia, R. A.. - In: INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW. - ISSN 0142-727X. - 25/3:(2004), pp. 384-392. [10.1016/j.ijheatfluidflow.2004.02.022]
Structure of turbulent channel flow with square bars on one wall
ORLANDI, Paolo;
2004
Abstract
The organised motion in a turbulent channel flow with a succession of square bars on the bottom wall has been investigated using direct numerical simulations. Several values of the ratio w/k, where k is the bar height and w is the longitudinal separation between consecutive bars have been examined in detail. Relative to a smooth surface, the streamwise extent of the near-wall structures is decreased while their spanwise extent is increased. As w/k increases, the coherence decreases in the streamwise direction having a minimum for w/k = 7. This is due to the outward motion occurring, most of all, near the leading edge of the elements. The Reynolds stress anisotropy tensor and its invariants show a closer approach to isotropy over the rough wall than over a smooth wall.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.