Transport enhancement mechanisms in open cavities
Transport enhancement mechanisms in open cavities
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DOI：
10.1017/s0022112001006917
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发表时间：
2002-02-10
影响因子：
3.7
通讯作者：
Ottino, JM
中科院分区：
文献类型：
--
作者：
Horner, M;Metcalfe, G;Ottino, JM
通过实验和计算，我们研究了两种在有惯性的二维开孔流动中增强输运的方法。首先，我们引入一个空间依赖性的速度场的壁驱动流的形状的周期性调制，这扰动的稳态流线在垂直于主流的方向。第二，我们引入了一个时间依赖性，通过瞬态加速-减速的平壁驱动流，令人惊讶的是，即使流线的肖像变化很小，在瞬态期间，仍然有显着的运输增强。研究的雷诺数和Reynolds-Strouhal数的范围在空间相关模式下为7.7 ≤ Re ≤ 46.5和0.52 ≤ ReSr ≤ 12.55，在时间相关模式下为12 ≤ Re ≤ 93和0.26 ≤ ReSr ≤ 5.02。依赖模式通过波瓣动力学理论上描述的运输。对于这两个修改，曲线与一个最大的特点时，绘制为强迫频率的函数的各种运输增强措施。定性分析表明，交换首先线性增加的强迫频率，然后减少为1/Sr的大频率。
By experiments and supporting computations we investigate two methods of transport enhancement in two-dimensional open cellular flows with inertia. First, we introduce a spatial dependence in the velocity field by periodic modulation of the shape of the wall driving the flow; this perturbs the steady-state streamlines in the direction perpendicular to the main flow. Second, we introduce a time dependence through transient acceleration-deceleration of a flat wall driving the flow; surprisingly, even though the streamline portrait changes very little during the transient, there is still significant transport enhancement. The range of Reynolds and Reynolds-Strouhal numbers studied is 7.7 less than or equal to Re less than or equal to 46.5 and 0.52 less than or equal to ReSr less than or equal to 12.55 in the spatially dependent mode and 12 less than or equal to Re less than or equal to 93 and 0.26 less than or equal to ReSr less than or equal to 5.02 in the time-dependent mode. The transport is described theoretically via lobe dynamics. For both modifications, a curve with one maximum characterizes the various transport enhancement measures when plotted as a function of the forcing frequency. A qualitative analysis suggests that the exchange first increases linearly with the forcing frequency and then decreases as 1/Sr for large frequencies.