A Lagrangian criterion of unsteady flow separation for two-dimensional periodic flows

作者：Han, Shuaibin; Zhang, Shuhai^*; Zhang, Hanxin

来源：Applied Mathematics and Mechanics, 2018, 39(7): 1007-1018.

DOI：10.1007/s10483-018-2350-8

• Lagrangian criterion
• unsteady flow separation
• finite-time Lyapunov exponent (FTLE)
• two-dimensional periodic flow

The present paper proposes a Lagrangian criterion of unsteady flow separation for two-dimensional periodic flows based on the principle of weighted averaging zero skin-friction given by Haller (HALLER, G. Exact theory of unsteady separation for two-dimensional flows. Journal of Fluid Mechanics, 512, 257-311 (2004)). By analyzing the distribution of the finite-time Lyapunov exponent (FTLE) along the no-slip wall, it can be found that the periodic separation takes place at the point of the zero FTLE. This new criterion is verified with an analytical solution of the separation bubble and a numerical simulation of lid-driven cavity flows.

• 出版日期2018-7
• 单位中国空气动力研究与发展中心