Direct numerical simulations of multifluid flows in a vertical channel undergoing topology changes
Direct numerical simulations of multifluid flows in a vertical channel undergoing topology changes
复制标题
DOI：
10.1103/physrevfluids.3.084401
复制
发表时间：
2018-08
影响因子：
2.7
通讯作者：
Jiacai Lu;G. Tryggvason
中科院分区：
文献类型：
--
作者：
Jiacai Lu;G. Tryggvason
通过直接数值模拟研究了垂直通道中的多流体流动，针对分隔不同流体的界面拓扑结构发生变化的情况。最初在湍流通道流中放置若干气泡，空隙率足够高，使得气泡发生碰撞，它们之间的液膜变得非常薄。当该液膜达到预定厚度时破裂，气泡得以聚并。对于高表面张力的情况，气泡会继续聚并，最终形成一个大气泡。另一方面，在低表面张力时，大气泡会再次破裂，有时会经历反复的聚并和破裂。对各种积分量（如平均流速、壁面剪切力和界面面积）的演变进行监测，并针对不同的控制参数进行比较。还研究了平行于壁面的平面上的流场和相分布的平均值，并使用低阶概率函数研究了统计稳态下的微观结构。
Multifluid flows in a vertical channel are examined by direct numerical simulations, for situations where the topology of the interface separating the different fluids changes. Several bubbles are initially placed in a turbulent channel flow at a sufficiently high void fraction so that the bubbles collide and the liquid film between them becomes very thin. This film is ruptured at a predetermined thickness and the bubbles are allowed to coalesce. For the cases with high surface tension the bubbles continue to coalesce, eventually forming one large bubble. At low surface tension, on the other hand, the large bubbles break up again, sometimes undergoing repeated coalescence and breakup. The evolution of various integral quantities, such as the average flow rate, wall-shear, and interface area are monitored and compared for different governing parameters. Averages of the flow field and the phase distribution over planes parallel to the walls are also examined, and the microstructure, at statistically steady state, is examined using low order probability functions.