Three-dimensionality effects in flow around two tandem cylinders

作者：Γεώργιος Παπαϊωάννου, Dick K. P. Yue, Michael S. Triantafyllou, George Em Karniadakis · 发表于：Journal of Fluid Mechanics · 年份：2006 · DOI：10.1017/s0022112006000139 · 被引用次数：167 · 研究领域：Fluid Dynamics and Vibration Analysis、Wind and Air Flow Studies、Fluid Dynamics and Turbulent Flows

The flow around two stationary cylinders in tandem arrangement at the laminar and early turbulent regime, ( $\hbox{\it Re}\,{=}\,10^2$ – $10^3$ ), is studied using two- and three-dimensional direct numerical simulations. A range of spacings between the cylinders from 1.1 to 5.0 diameters is considered with emphasis on identifying the effects of three-dimensionality and cylinder spacing as well as their coupling. To achieve this, we compare the two-dimensional with corresponding three-dimensional results as well as the tandem cylinder system results with those of a single cylinder. The critical spacing for vortex formation and shedding in the gap region depends on the Reynolds number. This dependence is associated with the formation length and base pressure suction variations of a single cylinder with Reynolds number. This association is useful in explaining some of the discrepancies between the two-dimensional and three-dimensional results. A major effect of three-dimensionality is in the exact value of the critical spacing, resulting in deviations from the two-dimensional predictions for the vorticity fields, the forces on the downstream cylinder, and the shedding frequency of the tandem system. Two-dimensional simulations under-predict the critical spacing, leading to erroneous results for the forces and shedding frequencies over a range of spacings where the flow is qualitatively different. To quantify the three-dimensional effects we first employ enstrophy, decomposed int...