A combined experimental and numerical approach to study the hierarchy of multiscale structures arising from the stationary solutal Marangoni instability

跨液界面的传质常常伴随着具有复杂和不规则流动结构的溶质Marangoni对流。这种所谓的界面湍流可以显著提高传质速率，在化学工程中具有相当重要的意义，例如在液-液萃取过程中。已知界面湍流通过类似级联的过程从小到大的长度尺度逐渐演变，其中越来越大的结构出现在较小的流动结构的背景上。这种层次演变显示了流动结构的特征序列，然后在一个显着更大的长度尺度上重复。这种演变的细节和各种流动结构的特征性质及其转换只是知之甚少。这些缺陷将通过该项目通过将精确的实验与光流测量的新技术相结合，并通过高分辨率的数值模拟来解决。要研究的特定配置是液-液系统，由两个不混溶的溶剂由平面界面分离。不同表面活性的溶质以及溶剂系统和容器几何形状的调整将用于选择不同层次的界面湍流级联。该数学模型结合了两个液相中的ow与界面浓度的单独传输方程，并考虑了表面活性剂的非线性吸附动力学。平面界面处界面湍流一般结构的相关数据将提供给基准质量优先计划的其他项目。在第二阶段，将讨论湍流叶栅中的高阶结构。除了改进传质模型的潜力外，对界面湍流的详细理解将为非线性动力学的其他领域（如反应扩散系统）开辟重要的概念联系。“

Mass transfer across liquid interfaces is frequently accompanied by solutal Marangoni convection with complex and irregular flow structures. This so-called interfacial turbulence, which can significantly enhance mass transfer rates, is of considerable importance in chemcial engineering, e.g. in liquid-liquid extraction processes. Interfacial turbulence is known to evolve progressively from small to large lengthscales by a cascade-like process, where larger and larger structures emerge on a background of smaller flow structures. This hierarchical evolution displays a characteristic sequence of flow structures before it is repeated on a significantly larger length scale. The details of this evolution and the characteristic properties of the various flow structures and their transformations are only poorly understood. These deficiencies will be addressed by the project through a combination of accurate experiments with novel techniques for optical flow measurement, and by highly resolved numerical simulations. The particular configuration to be studied is a liquid-liquid system, composed of two immiscible solvents separated by a plane interface. Solutes of different surfaceactivity together with a tuning of solvent system and container geometry will be used to select different hierarchy levels of the interfacial turbulence cascade. The mathematical model incorporates the ow in both liquid phases in connection with a separate transport equation of the interfacial concentration and takes a nonlinear sorption kinetics of the surfactant into account. Relevant data to the generic structures of interfacial turbulence at a plane interface will be provided to other projects of the priority programme in benchmark quality. In the second period, structures of higher order in the turbulence cascade will be addressed. Beside the potential to refine mass transfer models, the detailed understanding of interfacial turbulence will open important conceptual links to other areas of nonlinear dynamics such as reaction-diffusion systems.“