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

点击翻译按钮获取中文摘要

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.