Abstract In this paper, a dual splitter plate flow separation control device is introduced for a low Reynolds number flow (Re = 100) around the square cylinder of length L to achieve higher drag reduction and improved wake regime control compared to the conventional single splitter plate control devices. Here, two splitter plates of the same length W (ranging from 0.25 L to 2.50 L) are symmetrically attached on the rear surface along the horizontal centerline of the square cylinder with a spacing H (ranging from 0.0 L to 1.0 L) between them. The numerical study is performed using the in-house developed flexible forcing immersed boundary-lattice Boltzmann solver [1] to investigate the effects of dual splitter plate on the flow regime and flow-induced forces. The shear layer interaction with the splitter plates, as well as the vorticity and pressure distribution in the near wake region, are significantly modified by varying W and H, and four different flow regimes (Type I to Type IV) are identified from the observations. Among these flow types, the Type III flow pattern displays an accelerating flow in the wake region that is found to be most beneficial for higher base pressure recovery and drag reduction. Furthermore, dual splitter plates suppress von-Karman vortex shedding and lift force fluctuation, and produce higher drag reduction (≈ 21%) at less than half of the plate length of a single splitter plate. It is also noticed that a dual splitter plate configuration seems to be an optimum arrangement, since adding more splitter plates (up to 5 numbers were tested) on the rear surface of the square cylinder does not change the wake characteristics nor shows any improvements in the drag reduction.

中文翻译：

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双分流板增强方柱体减阻和尾流控制的数值研究

摘要 本文针对长度为 L 的方圆柱体周围的低雷诺数流 (Re = 100) 引入双分流板流动分离控制装置，与传统的单分流板相比，实现更高的减阻和改进的尾流状态控制。控制设备。这里，两块等长W（0.25L～2.50L）的分流板沿方筒的水平中心线对称地贴附在后表面，它们之间的间距为H（0.0L～1.0L）。数值研究是使用内部开发的柔性强制浸入式边界晶格 Boltzmann 求解器 [1] 进行的，以研究双分流板对流态和流致力的影响。剪切层与分流板的相互作用，以及近尾流区域的涡度和压力分布，通过改变 W 和 H 显着改变，并且从观察中确定了四种不同的流态（I 型到 IV 型）。在这些流动类型中，III 型流动模式在尾流区域显示出加速流动，被发现最有利于更高的基础压力恢复和减阻。此外，双分流板抑制了冯卡曼涡旋脱落和升力波动，并在不到单个分流板一半长度的情况下产生更高的减阻（≈ 21%）。还注意到双分流板配置似乎是最佳布置，