摘要
本文从近壁条带失稳的角度出发,采用直接数值模拟方法研究了不可压缩槽道湍流中发卡涡包的形成机制。研究表明,亚谐型弯曲模式低速条带的失稳可诱导出由多个严格对称和非对称的发卡涡组成的涡包结构。其中,严格对称的发卡涡由相邻低速条带间的碰撞导致,而非对称的发卡涡由低速条带的破碎导致。在条带的失稳过程中,高、低速流体之间的剪切是发卡涡形成的重要一环。该文结果不仅有助于深入认识壁湍流拟序结构演化的本质,而且对实际工程中壁湍流的应用和控制有一定的指导意义。
In this paper, from the perspective of the instability of the near wall streaks, the mechanisms on the formation of the hairpin vortex packets in incompressible turbulent channel flow are investigated by direct numerical simulation. The results show that the hairpin vortex packets which consist of several symmetrical and asymmetrical hairpin vortices can be induced by the instability of the subharmonic sinuous low-speed streaks. The symmetrical hairpin vortices are generated by the interaction between two adjacent low-speed streaks, while the asymmetrical hairpin vortices are formed by the breakdown of the low-speed streaks. During the instability processes of the streaks, the shearing between low- and high-speed fluids plays an important role in the formation of the hairpin vortex. The results can not only deepen the knowledge to recognize the evolutions of coherent structures, but also offer some guidance to use and control wall turbulence.
作者
李健
董刚
张辉
陈正寿
张建雷
LI Jian;DONG Gang;ZHANG Hui;CHEN Zheng-shou;ZHANG Jian-lei(School of Naval Architecture and Mechanical-Electrical Engineering, Zhejiang Ocean University, Zhoushan 316022, China;National Key Laboratory of Transient Physics, Nanjing University of Science and Technology, Nanjing 210094, China;Key Laboratory of Offshore Engineering Technology of Zhejiang Province, Zhoushan 316022, China)
出处
《船舶力学》
EI
CSCD
北大核心
2019年第8期883-892,共10页
Journal of Ship Mechanics
基金
浙江省自然科学基金（LQ18A020002）
上海交通大学海洋工程国家重点实验室开放课题（1814）
浙江省教育厅项目（Y201737053）
关键词
直接数值模拟
湍流拟序结构
条带
发卡涡包
direct numerical simulation
turbulent coherent structure
streak
hairpin vortex packet
