关于相速和临界雷诺兹数下降膜的洞察力
1Department of Applied Mechanics, <a href="https://ror.org/049tgcd06">Indian Institute of Technology Delhi</a>, Hauz Khas, New Delhi 110016, India.
Physical review. E
|July 18, 2024
概括
这项研究统一了粘性下降膜的相速和临界雷诺兹数. 一个独立于剪切应力的修改的雷诺兹数 (ReM) 预测了薄膜表面不稳定性的出现.
科学领域:
- 流体动力学 流体动力学
- 表面的不稳定性 表面的不稳定性
- 非牛顿流体动力学的流体动力学
背景情况:
- 粘性降落膜在各种工业过程中至关重要.
- 这些薄膜的表面不稳定性会影响热量和质量转移.
- 现有的模型经常将剪压和非剪压片单独处理.
研究的目的:
- 在重力驱动的粘性下降膜中建立相位速度和临界雷诺兹数的统一关系.
- 分析剪切应力对表面不稳定性的影响.
- 提供对落膜线性稳定性的新见解.
主要方法:
- 利用长波膨胀技术进行线性稳定性分析.
- 为相速和临界雷诺兹数获得分析表达式.
- 引入并分析了修改后的雷诺兹数 (ReM).
主要成果:
- 表面不稳定的临界雷诺德数取决于前沿阶段速度 (c0) 和倾斜角 (θ):[5/(2c0) ]cotθ.
- 修改后的雷诺兹数 (ReM) 确定不稳定性的开始,并且独立于表面剪切应力.
- 在长波模式下,ReM>5/2表示对剪切和非剪切膜的线性不稳定性.
结论:
- 建立了一个统一的框架来分析落膜的稳定性.
- 表面剪切应力不会影响不稳定的临界修改的雷诺兹数.
- 修改后的雷诺兹数 (ReM) 是一种控制粘性降落膜中长波表面不稳定的通用参数.
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