James Martin, Wilczek Michael
Max Planck Institute for Dynamics and Self-Organization (MPI DS), Am Faßberg 17, 37077, Göttingen, Germany.
Eur Phys J E Soft Matter. 2018 Feb 14;41(2):21. doi: 10.1140/epje/i2018-11625-8.
Cellular suspensions such as dense bacterial flows exhibit a turbulence-like phase under certain conditions. We study this phenomenon of "active turbulence" statistically by using numerical tools. Following Wensink et al. (Proc. Natl. Acad. Sci. U.S.A. 109, 14308 (2012)), we model active turbulence by means of a generalized Navier-Stokes equation. Two-point velocity statistics of active turbulence, both in the Eulerian and the Lagrangian frame, is explored. We characterize the scale-dependent features of two-point statistics in this system. Furthermore, we extend this statistical study with measurements of vortex dynamics in this system. Our observations suggest that the large-scale statistics of active turbulence is close to Gaussian with sub-Gaussian tails.
细胞悬浮液，如高密度细菌流，在某些条件下会呈现出类似湍流的相态。我们使用数值工具对这种“主动湍流”现象进行统计研究。遵循温辛克等人（《美国国家科学院院刊》109, 14308 (2012)）的方法，我们通过广义纳维-斯托克斯方程对主动湍流进行建模。研究了主动湍流在欧拉和拉格朗日框架下的两点速度统计。我们刻画了该系统中两点统计的尺度相关特征。此外，我们通过测量该系统中的涡旋动力学来扩展这项统计研究。我们的观察结果表明，主动湍流的大尺度统计接近高斯分布，但具有亚高斯尾部。
