Effect of pitching splitter plate on the wake topology and drag reduction of two square cylinders in tandem arrangement

IF 4.6 2区工程技术 Q1 ENGINEERING, CIVIL

Ocean Engineering Pub Date : 2025-04-21 DOI:10.1016/j.oceaneng.2025.121283

Prabir Sikdar , Sunil Manohar Dash

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引用次数: 0

Abstract

An active flow control mechanism using a hinged splitter plate is explored to modify wake topology and reduce drag of tandem square cylinders (TSCs) at pitch ratio of G/D = 6 and Reynolds Number Re = 100, where G represents the centre-to-centre spacing between cylinders of length D. The rigid plate is hinged at the midpoint of the upstream cylinder's rear face (HSPU). The governing parameters are pitching amplitudes (

θ_{m}

= 10°–20°), non-dimensional frequencies (

{S t}_{f} = f_{f} A / U

= 0.1 − 0.4), and length

(L_{f} / D

= 0–1) of the plate, which significantly affects wake structures, nature of vortex-interactions, pressure distribution, aerodynamic forces, power consumption, and effectiveness of drag reduction. Here,

f_{f}

and A are the pitching frequency and total excursion of the tail end of the plate, respectively. The free-stream velocity is U. Four distinct flow regimes are identified for the TSC-HSPU setup. Type – I involves von Karman vortex shedding, where the upstream cylinder vortex (UCV) dominates over the plate vortex (PV) in the cylinder gap region. For Type – II, bigger and stronger PVs induce a chain-like vortex pattern. In Type – III, PVs become sufficiently strong to inhibit UCVs shedding. In Type − IV, the strongest PVs interact with UCVs and generate a new vortex that dominates the cylinder gap region. Notably, Type − II and Type − III regimes yield lower drag. In comparison to TSC, the highest drag reduction of the TSC-HSPU setup is 47 %, obtained at

L_{f} / D

= 1.00,

{S t}_{f}

= 0.20, and

θ_{m}

= 10°.

查看原文本刊更多论文

俯仰分流板对两方圆柱串联布置尾流拓扑和减阻的影响

在螺距比为G/D = 6、雷诺数Re = 100 （G表示长度为D的圆柱体之间的中心间距）的条件下，探索了一种采用铰接分流板的主动流动控制机制，以改变尾迹拓扑并减小串联方形圆柱体（tsc）的阻力。刚性板铰接在上游圆柱体后面（HSPU）的中点。控制参数为俯仰幅度（θm = 10°-20°）、无量程频率（Stf=ffA/U = 0.1 - 0.4）和长度（Lf/D = 0-1），对尾流结构、涡相互作用性质、压力分布、气动力、功耗和减阻效果有显著影响。其中ff和A分别为板尾的俯仰频率和总偏移量。自由流速度为u。TSC-HSPU设置确定了四种不同的流动状态。I型为von Karman涡脱落，在柱面间隙区上游圆柱涡（UCV）占主导地位，而板涡（PV）占主导地位。对于II型，更大和更强的pv诱导链状涡型。在III型中，pv变得足够强大以抑制ucv的脱落。在−IV型中，最强的pv与ucv相互作用并产生一个新的涡，该涡主导圆柱体间隙区域。值得注意的是，型- II和型- III机制产生更低的阻力。与TSC相比，在f/D = 1.00、Stf = 0.20、θm = 10°时，TSC- hspu装置的最大减阻率为47%。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Ocean Engineering 工程技术-工程：大洋

CiteScore

7.30

自引率

34.00%

发文量

2379

审稿时长

8.1 months

期刊介绍： Ocean Engineering provides a medium for the publication of original research and development work in the field of ocean engineering. Ocean Engineering seeks papers in the following topics.