论文标题
过渡通道流中局部湍流的尺寸依赖性瞬态性质
Size-dependent transient nature of localized turbulence in transitional channel flow
论文作者
论文摘要
据报道，当雷诺数高于阈值时，通道流中的完全局部的湍流波段就会持续。在这里，我们证明了湍流带具有瞬态性质。当控制频带长度被固定时，湍流带的寿命似乎是随机的且指数分布的，这是无记忆的瞬态性质的迹象。除了随着雷诺数的增加而增加，平均寿命还随频带长度而大大增加。鉴于频带长度在实际通道流中总是随时间变化，因此这种尺寸依赖性可能会转化为时间依赖性，在阐明通道流过渡与定向渗透普遍性类之间的关系时，需要考虑到时间依赖性。
It has been reported that a fully localized turbulent band in channel flow becomes sustained when the Reynolds number is above a threshold. Here we show evidences that turbulent bands are of a transient nature instead. When the band length is controlled to be fixed, lifetimes of turbulent bands appear to be stochastic and exponentially distributed, a sign of a memoryless transient nature. Besides increasing with the Reynolds number, the mean lifetime also strongly increases with the band length. Given that the band length always changes over time in real channel flow, this size dependence may translate into a time dependence, which needs to be taken into account when clarifying the relationship between channel flow transition and the directed percolation universality class.
