摘要
以壁面脉冲扰动来构建湍流边界层近壁区对称与非对称相干结构理论模式,采用直接数值模拟的方法,研究了湍流边界层近壁区对称与非对称相干结构形成的理论机制和演化规律.计算结果显示非对称相干结构比对称相干结构更容易增长,这是由于非对称型结构能在湍流边界层近壁区域诱导产生较大的展向扰动速度,且不同初始结构类型分布对湍流边界层近壁区相干结构形成的动力学机制不同所致,从而加深了对近壁湍流边界层单个相干结构形成的某种动力学机制的认识理解.
The theoretical model of symmetrical and asymmetrical coherent structures in a near-wall turbulent boundary layer is established through study into the impulsive disturbance on the wall in this paper. Theoretical mechanism and evolution process of the coherent structures formation are studied by Direct Numerical Simulation （DNS）. The numerical result reveals that asymmetrical coherent structures are more likely to grow than symmetrical coherent structures,due to the larger span wise velocity induced by asymmetrical coherent structures in the near- wall area. And the dynamical mechanics of the coherent structures in the near-wall turbulent boundary layer vary with different distributions of initial structure. The proposed model relatively represents the real condition of fluid motion, and will help to improve the understanding of the dynamical mechanics of single coherent structure formation in the near-wall turbulent boundary layer.
出处
《南京信息工程大学学报（自然科学版）》
CAS
2012年第4期330-333,共4页
Journal of Nanjing University of Information Science & Technology（Natural Science Edition）
基金
国家自然科学基金(10872097)
国家863计划专项(2009AA03Z107)
关键词
近壁湍流边界层
壁面脉冲扰动
相干结构
near-wall turbulent boundary layer
impulsive disturbance
coherent structure
