Compressibility effects on the first global instability mode of the vortex formed in a regularized lid-driven cavity flow
Compressibility effects on the first global instability mode of the vortex formed in a regularized lid-driven cavity flow
复制标题
压缩性对规则化盖驱动腔流中形成的涡流第一全局不稳定模式的影响
DOI：
10.1016/j.compfluid.2016.12.008
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发表时间：
2017
影响因子：
2.8
通讯作者：
Yuya Ohmichi and Kojiro Suzuki
中科院分区：
文献类型：
--
作者：
井上良太;小池雅和;章ふぇいふぇい;田原淳一郎;Yuya Ohmichi and Kojiro Suzuki
本研究中使用全局线性稳定性分析研究了压缩性对二维 (2D) 盖驱动腔流稳定性的影响。在之前的一项研究中，贝加莫等人。 (2015) [12] 揭示了可压缩性对该流动的主要不稳定模式具有稳定作用。然而，这种稳定作用的详细机制尚未阐明。本研究的重点是这种对第一不稳定模式的稳定作用的机制，该稳定模式导致腔中形成的主涡流周期性振荡。我们的结果表明，由于涡量传递方程中出现的斜压扭矩和涡量膨胀项，可压缩性对该流动具有稳定作用。这些项的分布表明，涡度-膨胀效应抑制了扰动涡度的变化（即稳定了流动），斜压扭矩使扰动涡度分布变形。此外，通过求解强制压缩稳定性问题来定量估计斜压扭矩的影响，其中相应的线性化方程被人为地强制抵消斜压扭矩。结果清楚地表明斜压扭矩降低了第一不稳定模式的增长率。然而，由斜压扭矩引起的临界雷诺数的定量估计变化表明该项并不是稳定效应的最主要机制，并且膨胀效应会更显着。
The effect of compressibility on the stability of a two-dimensional (2D) lid-driven cavity flow was investigated using a global linear stability analysis in this study. In a previous study, Bergamo et al. (2015) [12] revealed that compressibility has a stabilizing effect on dominant instability modes of this flow. However, the detailed mechanism of this stabilization effect has not been elucidated. The present study focused on the mechanism of this stabilizing effect on the first instability mode which causes a periodic oscillation to a primary vortex formed in the cavity. Our results show that the compressibility has a stabilizing effect on this flow due to the baroclinic torque and vorticity-dilatation term which appear in the vorticity transport equation. The distribution of these terms show that the vorticity-dilatation effect suppresses the changes in the perturbed vorticity (i.e., stabilizes the flow), and the baroclinic torque deforms the perturbed vorticity distribution. Furthermore, the effect of baroclinic torque was quantitatively estimated by solving the forced compressible stability problem in which the corresponding linearized equations are artificially forced to cancel the baroclinic torque. The results clearly show that the baroclinic torque decreases the growth rate of the first instability mode. However, the quantitatively estimated variation in the critical Reynolds number caused by the baroclinic torque indicates this term is not the most dominant mechanism of the stabilization effect and dilatation effects would be more significant.