| 尚文强,张莹,陈昭奇,袁志平,董博恒.基于FTM方法的二维Kelvin-Helmholtz不稳定性数值模拟[J].计算力学学报,2018,35(4):424~430 |
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| 基于FTM方法的二维Kelvin-Helmholtz不稳定性数值模拟 |
| Numerical simulation of two-dimensional Kelvin-Helmholtz instabilities using a front tracking method |
| 投稿时间：2017-05-12 修订日期：2017-07-28 |
| DOI：10.7511/jslx20170512003 |
| 中文关键词: Kelvin-Helmholtz不稳定性 速度梯度层厚度 Neumann边界条件 Dirichlet边界条件 界面跟踪法 |
| 英文关键词:Kelvin-Helmholtz instability thickness of velocity gradient layers neumann boundary condition dirichlet boundary condition front tracking method |
| 基金项目:国家自然科学基金（11562011）；江西省自然科学基金（20151BAB202002）资助项目. |
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| 中文摘要: |
| 使用界面跟踪法FTM（Front Tracking Method）对二维不混溶、不可压缩流体的K-H（Kelvin-Helmholtz）不稳定性进行数值模拟。研究表明，速度梯度层越厚，界面在水平分量中移动越快，卷起越少；初始水平速度差越大，界面卷起越多，内扰动增长速度越快，K-H不稳定性的特征形式更加明显；此外，在Neumann边界条件（即无滑移边界条件）下界面的扰动发展得比Dirichlet边界条件（即对称边界条件）下的扰动快。由于Dirichlet边界中的边界层，在开始时刻涡量扩展到两侧，影响了K-H不稳定性的生长速率；而在Neumann边界条件下涡量由于初始水平速度差，在界面中心聚集。最后，研究了不同边界条件下各种理查德森数对K-H不稳定性的影响。 |
| 英文摘要: |
| The two-dimensional Kelvin-Helmholtz (K-H) instability of immiscible and incompressible fluids is performed using a front tracking method.It is shown that the thicker the velocity gradient layer,the faster the interface moves in horizontal component and the less the roll-up less.It is also found that the greater the initial horizontal velocity difference,the more the interface roll-up and the higher the inward disturbance growth rate,and the characteristic form of K-H instability becomes much more obvious.Besides,we also observe that the disturbance of interface in Neumann boundary condition(that is no slip boundary condition) develops faster than the disturbance in Dirichlet boundary condition(that is symmetrical boundary condition).Due to the existence of boundary layer in Dirichlet boundary,vorticity has begun to spread to both sides at the initial moment,affecting the growth rate of the K-H instability while vorticity gathers in the center of interface due to initial horizontal velocity differences in Neumann boundary condition.Finally we investigated the effect of a various values of Richardson number in different boundary conditions on the K-H instability. |
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