Three-dimensional wake instabilities behind side-by-side foils at a moderate Reynolds number

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow Pub Date : 2025-09-15 DOI:10.1016/j.ijheatfluidflow.2025.110050

Priscila Portocarrero , Ahmet Gungor , Suyash Verma , Muhammad Saif Ullah Khalid , Arman Hemmati

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Abstract

Three-dimensional instabilities in the wake behind side-by-side pitching foils are numerically evaluated at Reynolds number of 8000, considering different separation distances (0.5c < d < 1.5c) and Strouhal numbers (St = 0.3 and 0.5) for both in-phase (ϕ = 0) and out-of-phase (ϕ = π) oscillations. Here, c is the foil chord. This parameter space enables the identification and categorization of three-dimensional instabilities behind side-by-side pitching foils. Distinct three-dimensional wake topology regimes are identified and their characteristics are linked to foil kinematics. Four types of Instability Modes Evolution (IME) of three-dimensional spanwise instabilities are identified within this parameter space: IME type 2, IME type 1A, IME type 1B, and IME type 0. These modes differ based on the proximity effect between the foils and the transition to the final wake pattern. The study also identifies key kinematic and geometric thresholds associated with each IME type.

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中等雷诺数下平行尾翼后的三维尾迹不稳定性

考虑到不同的分离距离（0.5c < d < 1.5c）和斯特罗哈尔数（St = 0.3和0.5），对同相（φ = 0）和非相（φ = π）振荡，在8000雷诺数下对并排俯仰箔后尾迹的三维不稳定性进行了数值评估。这里，c是陪衬和弦。该参数空间使识别和分类的三维不稳定性背后的并排俯仰箔。确定了不同的三维尾迹拓扑结构，并将其特征与箔体运动学联系起来。在该参数空间内，确定了四种三维跨向不稳定性的不稳定模态演化（IME）： IME型2、IME型1A、IME型1B和IME型0。这些模式的不同是基于箔片之间的接近效应和向最终尾迹模式的过渡。该研究还确定了与每种IME类型相关的关键运动学和几何阈值。

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

International Journal of Heat and Fluid Flow 工程技术-工程：机械

CiteScore

5.00

自引率

7.70%

发文量

131

审稿时长

33 days

期刊介绍： The International Journal of Heat and Fluid Flow welcomes high-quality original contributions on experimental, computational, and physical aspects of convective heat transfer and fluid dynamics relevant to engineering or the environment, including multiphase and microscale flows. Papers reporting the application of these disciplines to design and development, with emphasis on new technological fields, are also welcomed. Some of these new fields include microscale electronic and mechanical systems; medical and biological systems; and thermal and flow control in both the internal and external environment.