小波浪粗糙度对平板边界层自然过渡的影响

IF 0.7 Q4 MECHANICS

Journal of Fluid Science and Technology Pub Date : 2021-01-01 DOI:10.1299/jfst.2021jfst0008

Hiroki Tameike, A. Yakeno, S. Obayashi

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引用次数: 2

摘要

减少翼型周围粘滞阻力的有效方法之一是通过延迟边界层过渡。在这项研究中，我们分析了小波浪粗糙度对二维自然边界层过渡的影响，使用直接数值模拟来解决每个小粗糙度。对波浪粗糙度波长进行了参数化研究。我们的结果表明，在某些情况下，过渡延迟的特征取决于粗糙度波长。在详细分析中，我们发现波浪粗糙度首先影响初级涡的生长过程，即TS不稳定性。此外，我们发现二次涡配对也依赖于它。在大多数过渡延迟情况下，粗糙度波长与TS不稳定波长相差甚远，且上游先发生涡对，下游发生涡对较少，使涡大小保持较小。

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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Influence of small wavy roughness on flatplate boundary layer natural transition

One of the effective ways to reduce viscous drag around an airfoil is by delaying the boundary layer transition. In this study, we analyzed the influence of a small wavy roughness on a two-dimensional, natural boundary layer transition, using direct numerical simulation that resolved each small roughness. A parametric study was conducted on the wavy roughness wavelength. Our results show that in some cases the transition delays whose characteristics depend on the roughness wavelength. In a detailed analysis, we found that the wavy roughness firstly affects the process of primary vortex growth, Tollmien–Schlichting (TS) instability. In addition, we found that the secondary vortex pairing also depended on it. In the most transition-delayed cases, the roughness wavelength was different far from the TS instability one, and the vortex pairing occurred firstly in upstream however not much in downstream, keeping the vortex size is kept small.

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来源期刊

Journal of Fluid Science and Technology MECHANICS-

CiteScore

1.00

自引率

12.50%

发文量

期刊介绍： Journal of Fluid Science and Technology (JFST) is an international journal published by the Fluids Engineering Division in the Japan Society of Mechanical Engineers (JSME). JSME had been publishing Bulletin of the JSME (1958-1986) and JSME International Journal (1987-2006) by the continuous volume numbers. Considering the recent circumstances of the academic journals in the field of mechanical engineering, JSME reorganized the journal editorial system. Namely, JSME discontinued former International Journals and projected new publications from the divisions belonging to JSME. The Fluids Engineering Division acted quickly among all divisions and launched the premiere issue of JFST in January 2006. JFST aims at contributing to the development of fluid engineering by publishing superior papers of the scientific and technological studies in this field. The editorial committee will make all efforts for promoting strictly fair and speedy review for submitted articles. All JFST papers will be available for free at the website of J-STAGE (http://www.i-product.biz/jsme/eng/), which is hosted by Japan Science and Technology Agency (JST). Thus papers can be accessed worldwide by lead scientists and engineers. In addition, authors can express their results variedly by high-quality color drawings and pictures. JFST invites the submission of original papers on wide variety of fields related to fluid mechanics and fluid engineering. The topics to be treated should be corresponding to the following keywords of the Fluids Engineering Division of the JSME. Basic keywords include: turbulent flow; multiphase flow; non-Newtonian fluids; functional fluids; quantum and molecular dynamics; wave; acoustics; vibration; free surface flows; cavitation; fluid machinery; computational fluid dynamics (CFD); experimental fluid dynamics (EFD); Bio-fluid.