在表面粘性领域的曲率和形状放松
Joseph M Barakat1, Todd M Squires1
1Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106.
概括
这项研究模拟了曲的粘性流体接口,揭示了表面曲率如何产生流动并影响域形状. 关键毛细血管数 (Ca) 表示形状不稳定性,与萨夫曼-泰勒指纹不同.
科学领域:
- 流体力学 流体力学 流体力学
- 表面科学是一门学科.
- 类风病学 类风病学 类风病学
背景情况:
- 对工程和生物应用而言,模拟质复杂的接口至关重要.
- 现有的模型通常将接口简化为平面或固定曲率,忽视动态曲率效应.
- 了解充满表面活性剂的曲面接口需要动态模型来解释表面粘度和变化的几何形状.
研究的目的:
- 在曲面接口上研究一个双相表面流体的动态模型.
- 了解表面曲率变化如何在粘性域内产生二维斯托克斯流.
- 分析由此产生的对曲率变形和域形状扭曲的阻力.
主要方法:
- 在半径随时间变化的球形接口上开发了表面粘性域的动态模型.
- 使用了Boussinesq-Scriven构成方程,用于在小幅度曲率变形下表面应力.
- 在压差的正弦振荡下分析了依赖频率的动态,定义了佩克莱特数 (Pe).
主要成果:
- 曲率放松是扩散性的,以佩克莱特数 (Pe) 为特征.
- 在高Pe时,形成了尖的边界层,导致不连续的域曲率.
- 在临界表面毛细血管数 (Ca) 上出现形状不稳定,由表面粘性应力驱动,与萨夫曼-泰勒指纹不同.
结论:
- 表面粘度显著影响曲线接口和域形状的动态.
- 该研究定义了关键的无维数 (Pe,Ca) 定义在变形下控制接口行为.
- 这些发现为建模更复杂的界面现象提供了基础,包括粘性弹性和大变形.
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