Hoi Su Min, Ooi Ean Hin, Chew Irene Mei Leng, Foo Ji Jinn
School of Engineering, Monash University Malaysia, 47500, Bandar Sunway, Selangor, Malaysia.
Sci Rep. 2022 Jan 7;12(1):76. doi: 10.1038/s41598-021-02872-1.
A 3D stationary particle tracking velocimetry (SPTV) with a unique recursive corrective algorithm has been successfully established to detect the instantaneous regional fluid flow characteristics. The veracity of SPTV is corroborated by conducting actual displacement measurement validation, which gives a maximum percentage deviation of about 0.8%. This supports the accuracy of the current SPTV system in 3D position detection. More importantly, the SPTV detected velocity fluctuations are highly repeatable. In this study, SPTV is proven to be able to express the nature of chaotic fractal grid-induced regional turbulence, namely: the high turbulence intensity attributed to multilength-scale wake interactions, the Kolmogorov's -5/3 law decay, vortex shedding, and the Gaussian flow undulations immediately leeward of the grid followed by non-Gaussian behaviour further downstream. Moreover, by comparing the flow fields between control no-grid and fractal grid-generated turbulence of a plate-fin array, SPTV reveals vigorous turbulence intensity, smaller regional integral-length-scale, and energetic vortex shedding at higher frequency for the latter, particularly between fins. Thereupon, it allows the unravelling of detailed thermofluid interplays of plate-fin heat sink heat transfer augmentation. The novelty of SPTV lies in its simplicity, use of low-cost off-the-shelf components, and most remarkably, low computational complexity in detecting fundamental characteristics of turbulent fluid flow.
一种具有独特递归校正算法的三维固定粒子跟踪测速技术(SPTV)已成功建立,用于检测瞬时区域流体流动特性。通过实际位移测量验证证实了SPTV的准确性,其最大百分比偏差约为0.8%。这支持了当前SPTV系统在三维位置检测中的准确性。更重要的是,SPTV检测到的速度波动具有高度可重复性。在本研究中,SPTV被证明能够表达混沌分形网格诱导的区域湍流的性质,即:归因于多长度尺度尾流相互作用的高湍流强度、柯尔莫哥洛夫-5/3定律衰减、涡旋脱落,以及网格下游立即出现的高斯流波动,随后在更下游出现非高斯行为。此外,通过比较无网格控制和板翅阵列分形网格产生的湍流之间的流场,SPTV揭示了后者具有更强的湍流强度、更小的区域积分长度尺度以及更高频率的强烈涡旋脱落,特别是在翅片之间。因此,它能够揭示板翅式散热器传热增强的详细热流体相互作用。SPTV的新颖之处在于其简单性、使用低成本的现成组件,以及最显著的是,在检测湍流流体流动基本特征时具有低计算复杂性。