Nonlinear dynamics of free liquid surfaces: Controlled splitting of a liquid jet

自由液体表面的非线性动力学：液体射流的受控分裂

• 批准号: 73295831
• 负责人: Professor Dr. Tobias Manuel Schneider
• 金额: --
• 依托单位: Department of Physics
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/73295831?language=en
• 关键词: Nonlinear; dynamics; free; liquid; surfaces

The fragmentation of a water stream from a faucet into a sequence of drops is aneveryday example of a hydrodynamical flow undergoing a topological transition from a connected cylinder to separated drops. Studies of this breakup including the highly nonlinear dynamics at pinch-off did not only lead to the development of new mathematical methods to deal with the emerging singularities but also allowed to control the drop formation in relevant technological processes like inkjet printingWe aim at studying such transitions in free-surface flows specifically focusing on controlled Splitting of a liquid jet into two subfilaments (instead of its decay into droplets) (cf. Fig. la). While a first approach to describe the phenomenon theoretically considered a free-flowing Newtonian jet (Paruchuri & Brenner), first attempts to experimentally demonstrate controlled jet Splitting focus on a microfluidic setup where a polymeric fluid jet is surrounded by another co-flowing liquid. In close cooperation with experimentalists, we plan to extend the theoretical analysis of Paruchuri and Brenner to the technologically more relevant two-phase flow Situation and to demonstrate controlled jet Splitting. Jet Splitting does not only constitute an interesting fundamental fluid dynamical problem but is also of technological relevance äs it may provide a novel route to producing small fibers and may form the basis of a new non-droplet-based, continuous-now microfmidics.

从水龙头流出的水流分裂成一系列的水滴，这是流体动力学流动从相连的圆柱体到分离的水滴的拓扑转变的一个日常例子。对这种断裂的研究，包括夹断处的高度非线性动力学，不仅导致了新的数学方法的发展，以处理出现的奇异性，而且还允许在相关的技术过程中控制液滴的形成，如喷墨打印。（而不是衰变成液滴）（参见图la）。虽然第一种方法来描述理论上被认为是自由流动的牛顿射流的现象（Paruchuri和Brenner），但第一次尝试在实验上证明受控射流分裂集中在微流体设置上，其中聚合物流体射流被另一种共同流动的液体包围。在与实验人员的密切合作中，我们计划将Paruchuri和Brenner的理论分析扩展到技术上更相关的两相流情况，并演示受控射流分裂。射流分裂不仅构成了一个有趣的基本流体动力学问题，而且还具有技术相关性，因为它可以提供一种生产小纤维的新途径，并可能形成一种新的非液滴型、连续型微流体的基础。