Numerical simulation of Marangoni convection in a shallow rectangular cavity with a linear solutal boundary condition
Numerical simulation of Marangoni convection in a shallow rectangular cavity with a linear solutal boundary condition
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DOI：
10.1016/j.ijheatmasstransfer.2021.121578
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发表时间：
2021-10
影响因子：
5.2
通讯作者：
Jiangao Zhang;Y. Okano;S. Dost
中科院分区：
文献类型：
--
作者：
Jiangao Zhang;Y. Okano;S. Dost
对矩形浅腔中线性溶质边界条件下的Marangoni对流进行了一系列三维数值模拟。对于工作流体，选择两个施密特数值（中等和高）（Sc = 10和100）。计算得到的流速和浓度分布比以往采用定常溶质边界条件的计算结果更为独特和复杂。结果还表明，流动是稳定的，在一个相对较小的溶质Marangoni数。出现了嵌入在液体层中的二次涡。旋涡的发展数量与所选择的溶质Marangoni数和施密特数的大小密切相关。当溶质的Marangoni数超过一个临界值时，Marangoni流失去其稳定性，并发展成三维振荡流。对于振荡流，与定常边界条件相比，虽然在中等施密特数下，线性边界条件下可以观察到从混沌到振荡的后向过渡，但在相同的Marangoni数水平上，这种后向过渡的扰动能量总是较弱。流动不稳定性的演化序列与施密特数有关，因为在较高的施密特数下会出现二次波。此外，由于腔边界的影响，波型在传播过程中经历了一系列的演化，即膨胀、分离、压缩和合并。结果，由于波被限制在矩形腔中，所以在域中发展出样条形、马蹄形和楔形的波图案。
A series of three-dimensional numerical simulations have been carried out to examine the characteristics of Marangoni convection in a shallow rectangular cavity that is subjected to a linear solutal boundary condition. For the working fluid, two Schmidt number values (moderate and high)(S c= 10 and 100) are chosen. The computed flow velocity and concentration distributions show more unique and complex characteristics compared with those of previous studies used a constant solutal boundary condition. Results also indicate that the flow is steady at a relatively small solutal Marangoni number. The secondary vortices embedded in the liquid layer appear. Number of vortices develop greatly depends on the levels of selected solutal Marangoni and Schmidt numbers. When the solutal Marangoni number exceeds a critical value, the Marangoni flow losses its stability, and a three-dimensional oscillatory flow develops. For the oscillatory flow, compared with the case of constant boundary condition, although a backward transition from chaotic to oscillatory is observed with the use of linear boundary condition at a moderate Schmidt number, the disturbance energy of that is always weaker at the same Marangoni number levels. The evolution sequences of flow instabilities are related to the Schmidt number due to the occurrence of a secondary wave at a higher Schmidt number. In addition, the wave patterns undergo a series of evolutions, namely, expansion, separation, squeezing, and merging during propagation due to the effect of cavity boundaries. As a result, since the waves are confined within the rectangular cavity, the wave patterns of spline-like, horseshoe-like, and wedge-like develop in the domain.