TY - GEN
T1 - Effects of roughness elements on the separation of laminar boundary layers
AU - Beratlis, N.
AU - Vizard, A.
AU - Squires, Kyle
AU - Balaras, E.
N1 - Funding Information:
EB and AV where partially supported by the National Science Foundation Grand CBET-0933642. This work used the Saguaro high-performance computer cluster at ASU’s Advanced Computing Center, and the Extreme Science and Engineering Discovery Environment, XSEDE (award TG-CTS110028).
PY - 2013
Y1 - 2013
N2 - A series of direct numerical simulations (DNS) of the flow past a zero pressure gradient flat plate with rows of dimples is carried out. The Reynolds number based on the boundary layer thickness is 1000 and the dimples have a circular profile with a depth to diameter ratio of 0.1. The incoming flow is laminar and the ratio of the incoming boundary layer thickness to the dimple depth determines the critical Reynolds number, where transition to turbulence occurs downstream. This happens as the shear layer that forms at the dimple edge separates over the first row of dimples and becomes unstable creating coherent vortex sheet. The vortex sheet undergoes a complex spanwise instability transforming themselves into a packet of horseshoe vortices. As a result the boundary layer downstream of the dimples has the same qualitative features encountered in wall bounded turbulent boundary layers.
AB - A series of direct numerical simulations (DNS) of the flow past a zero pressure gradient flat plate with rows of dimples is carried out. The Reynolds number based on the boundary layer thickness is 1000 and the dimples have a circular profile with a depth to diameter ratio of 0.1. The incoming flow is laminar and the ratio of the incoming boundary layer thickness to the dimple depth determines the critical Reynolds number, where transition to turbulence occurs downstream. This happens as the shear layer that forms at the dimple edge separates over the first row of dimples and becomes unstable creating coherent vortex sheet. The vortex sheet undergoes a complex spanwise instability transforming themselves into a packet of horseshoe vortices. As a result the boundary layer downstream of the dimples has the same qualitative features encountered in wall bounded turbulent boundary layers.
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M3 - Conference contribution
AN - SCOPUS:85034022364
T3 - International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
BT - International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
PB - TSFP-8
T2 - 8th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013
Y2 - 28 August 2013 through 30 August 2013
ER -