《TAML》好文推荐: 湍流边界层中内外区相互作用机理探索

研究亮点：

(1) 采用交互式本征正交分解技术来研究湍流边界层中内外区相互作用规律；

(2)外区大尺度流动对近壁小尺度结构具有叠加和调制作用；

(3)展向的频率调制效应与流向的频率调制效应相反。

（a）

(b)

（a）大尺度速度（彩色云图）与小尺度脉动（黑色等值线）的空间分布；（b）展向的频率调制效应。

本文主要采用交互式本征正交分解（interactive POD）技术探讨湍流边界层中外区大尺度运动对近壁小尺度流动结构的振幅和频率调制效应，所用数据为雷诺数Re_τ =550和1000的充分发展槽道流。分别研究了外区大尺度结构对流向速度u、法向速度v、展向速度w、以及雷诺切应力−uv的振幅和频率调制效应。结果表明：雷诺应力的振幅调制效应明显强于其他速度分量；同时，在湍流边界层近壁区，展向的频率调制效应与流向的频率调制效应相反，即展向的特征频率随着外区大尺度速度的增大而减小。

  The amplitude and frequency modulation of near-wallflow structures by the large-scale motions in outer regions is studied inturbulent channel flows. The proper orthogonal decomposition (POD) method isapplied to investigate the interactions between the near-wall motions and thelarge-scale flow modes of the outer regions based on two datasets from directnumerical simulation of turbulent channel flows at Reynolds numbers of 550 and 1000.The fluctuations in the fields u⁺, v⁺, w⁺ and Reynolds shearstress −(uv)⁺ are studied tounderstand the mechanism of amplitude and frequency modulation of the near-wallstructures by the outer large-scale motions. The amplitude modulationcoefficient of the Reynolds shear stress is larger than that of the velocitycomponents. The frequency modulation effect has an opposite influence in thespanwise direction compared to the streamwise direction. The streamwisecharacteristic frequency increases with increasing large-scale velocity.However, the spanwise characteristic frequency exhibits a decreasing trend withincreasing large-scale velocity in the near-wall region.

关于本刊

Theoretical & Applied Mechanics Letters《力学快报（英文）》是中科院力学研究所和中国力学学会联合主办的开放获取英文学术期刊，何国威院士和黄永刚院士任联合主编。主要报道与理论、计算和实验力学相关的创新性前沿研究，包括但不限于航空航天、海洋工程、能源环境、材料结构、机械与运输工程等领域。目前期刊已被ESCI, Scopus, CSCD, CJCR, DOAJ等数据库收录。2020年Scopus的CiteScore为2.1，位于计算力学类的Q2区。全文免费下载阅读（https://www.sciencedirect.com/journal/theoretical-and-applied-mechanics-letters），欢迎关注和投稿。

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