论文标题
平面轴向流的降低排序盖金模型
Reduced-order Galerkin models of plane Couette flow
论文作者
论文摘要
使用系列投影衍生出平面轴向流的降级模型，其正顺式基函数是线性化的Navier-Stokes系统的领先可控性模式，用于一些低波数。由此产生的Galerkin系统包含普通微分方程，其自由度从144到600，可以集成到大时段，而没有数值不稳定的迹象。尽管系统自由度在系统的自由度上截断了数量级，但也发现如此获得的降级模型还可以匹配雷诺数字500和1200的直接数值模拟的统计数据。因此，当前模型在规范壁结合的流动中提供了有趣的折衷，其模式相对较少，代表流动中相干结构及其主要动力学。
Reduced-order models were derived for plane Couette flow using Galerkin projection, with orthonormal basis functions taken as the leading controllability modes of the linearised Navier-Stokes system for a few low wavenumbers. Resulting Galerkin systems comprise ordinary differential equations, with a number of degrees of freedom ranging from 144 to 600, which may be integrated to large times without sign of numerical instability. The reduced-order models so obtained are also found to match statistics of direct numerical simulations at Reynolds number 500 and 1200 with reasonable accuracy, despite a truncation of orders of magnitude in the degrees of freedom of the system. The present models offer thus an interesting compromise between simplicity and accuracy in a canonical wall-bounded flow, with relatively few modes representing coherent structures in the flow and their dominant dynamics.
