4.7 Article

Linear stability analysis of two fluid columns of different densities and viscosities in a gravity field

期刊

JOURNAL OF FLUID MECHANICS
卷 920, 期 -, 页码 -

出版社

CAMBRIDGE UNIV PRESS
DOI: 10.1017/jfm.2021.440

关键词

baroclinic flows; shear layers

资金

  1. Department of Energy, National Nuclear Security Administration [DE-NA0002382]
  2. California Institute of Technology

向作者/读者索取更多资源

This study investigates the linear stability of a vertical interface separating two miscible fluid columns of different densities and viscosities under the influence of gravity, showing how disturbances grow over time depending on wave numbers and flow parameters. It is found that the growth rate of perturbation energy is influenced by small wavenumbers initially, dominated by two-dimensional modes, with substantial transient growth observed at higher wave modes initially followed by decay over time. Sensitivity analysis on perturbation growth with respect to initial time, density, and viscosity ratios is also conducted.
The linear stability of a vertical interface separating two miscible fluid columns of different densities and viscosities under the influence of gravity is investigated. This flow possesses a time-dependent reference state (each column accelerates at different rates owing to their different densities) and the interface thickness grows as the square root of time (by diffusion). Numerical integration of the linear initial-value problem is carried out and discussed in detail as a function of vertical and spanwise wavenumbers and the flow parameters. Adjoint-based optimization is performed in order to determine initial conditions that lead to maximum growth of disturbances in finite time. Results indicate that the rate of growth of the perturbation energy at small wavenumbers (less affected by viscosity initially) is dominated by two-dimensional modes (no spanwise variation). Substantial transient growth is observed at higher wave modes initially, followed by asymptotic decay of the perturbations at large time. Sensitivity of perturbation growth with respect to initial time, density and viscosity ratios is investigated. This work is complementary to previous inviscid analysis of this configuration, which showed that the interface was unconditionally unstable at all wave modes, even in the presence of surface tension, and that instability grew as the exponential of time squared.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据