Department of Mechanical Engineering , Korea National University of Transportation , Chungju 27469 , Republic of Korea.
Langmuir. 2018 Jun 26;34(25):7465-7471. doi: 10.1021/acs.langmuir.8b01355. Epub 2018 Jun 13.
Controlling drop dynamics on solid surfaces is an important challenge. In many strategies for efficient drop deposition, drop dynamics is generally assumed to be axisymmetrical. We demonstrate shape-dependent impact dynamics that can considerably modify the dynamics by deforming the drop into a truncated spherical shape at the impact moment. Experimental and numerical studies show the exceptional rim dynamics that lead to reduced bounce heights compared with spherical drops. We investigate the impact dynamics of truncated spherical drops as a function of the truncation depth, surface wettability, and impact velocity numerically. The bounce height of the truncated drop reduces by 56% below spherical drops. To elucidate the mechanism for the reduction in the bounce height, we conduct the horizontal and vertical momentum analyses of truncated drops. The truncated drop impact can potentially open up new opportunities for enhancing drop deposition in practical applications, such as surface coating and spray cooling.
控制固液表面的液滴动力学是一项重要的挑战。在许多高效液滴沉积策略中，通常假设液滴动力学是轴对称的。我们展示了依赖于形状的冲击动力学，通过在冲击时刻将液滴变形为截头球形，可以显著改变动力学。实验和数值研究表明，边缘动力学异常，导致与球形液滴相比，反弹高度降低。我们通过数值模拟研究了作为截头深度、表面润湿性和冲击速度函数的截头球形液滴的冲击动力学。截头液滴的反弹高度比球形液滴降低了 56%。为了阐明反弹高度降低的机制，我们对截头液滴进行了水平和垂直动量分析。截头液滴冲击可能为提高实际应用中的液滴沉积（如表面涂层和喷雾冷却）开辟新的机会。
