基底壁面变形运动对粘弹性液膜流动特性影响机理和控制方法研究

液膜流动现象在自然界和人类日常生产和生活中广泛存在。液膜动力学特性及其流动的稳定性是生产加工、地球物理和生物物理等众多领域中的关键问题。本项目拟采用基于长波近似的线性和弱非线性理论分析方法和基于锐利界面法的直接数值模拟方法，以平面问题和管道环流问题为例，系统研究基底壁面结构及其变形运动对粘弹性液膜流动特性的影响规律和机制，揭示流体惯性、表面张力以及流体黏弹性与基底壁面非定常运动之间的耦合激励或抑制效应；在此基础上，建立基于基底结构与变形运动的黏弹性液膜流动主、被动控制方法。对关键控制参数及其取值空间进行辨识，并进行相应的实验验证。从而实现黏弹性液膜流动失稳过程及失稳后液膜自由面波动力学特性（振幅、波速、流量等）的主、被动控制。相关研究对于提高聚合物薄膜制造、表面喷涂以及表面化学反应等工业生产过程效率和产品质量具有重要的指导意义。

The dynamics of falling films subjected to an external driving force is a ubiquitous and essential phenomenon that occurs extensively in nature and industrial applications. The film stability is the key issue in many manufacturing processes (coating films and spray forming), geophysics, and biophysics. In this proposal, the influences of substrate topography and deformation on the film dynamics of planar and core annular flow are studied comprehensively according to the linear and weak non-linear theoretical analysis, and the direct numerical simulation based on the sharp interface method. The interactions between the flow inertia, surface tension, film viscoelasticity, and the transient movement of the substrate are mainly concerned. Moreover, passive and active control methods are established based on the topography and deformation movement of the substrate. The key parameters and their values are identified, and corresponding experimental verification is performed. Thus, the instability of viscoelastic liquid film flow and the dynamics of the free surface wave (amplitude, wave velocity, flow rate, etc.) can be achieved. Corresponding results are significant and helpful in improving the efficiency and product quality of industrial production, such as polymer film manufacturing, surface coating, and interfacial chemical reactions.