Event № 835
Numerical simulation of hydrodynamics, heat and mass transport as well as phase change in thin liquid films is an extremely challenging task, owing to large discrepancy between the involved length scales and to complex interface dynamics (interfacial waves, Marangoni-induced film deformation, de- and rewetting etc.). The degree of complexity further increases for films on substrates with topography, deformable substrates and on substrates with graded properties. Combining analytical and numerical methods allows an accurate description of film hydrodynamics and transport processes with reasonable effort. In this talk the long-wave theory and Graetz-Nusselt theory, and their application to description of hydrodynamics and heat and mass transport in liquid films on plain and modified substrates is demonstrated.
Long-wave theory is a typical example of successful combination of analytical and numerical methods for solutions of film flow problems. The full system of governing equations reduces in the framework of this theory to a single evolution equation for the film thickness. An additional modelling step is necessary if the transport processes in the wall wetted by the film or in the ambient gas can’t be treated using the long-wave approximation.
The Graetz-Nusselt approach is usually applied to description of thermally developing region in channels and ducts. This theory has been extended to describe the heat transport in liquid films flowing down walls with longitudinal grooves of arbitrary cross-section geometry.