Experimental investigation of initial instabilities of a liquid film

• Grant number: 17/06303-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2017
• End date: June 30, 2018
• Field of knowledge: Engineering - Mechanical Engineering - Transport Phenomena
• Principal Investigator: Erick de Moraes Franklin
• Grantee: Lucas Lima da Silva
• Host Institution: Faculdade de Engenharia Mecânica (FEM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

When in the presence of a free surface, inertial effects may be at the origin of instabilities giving rise to surface waves. When the fluid flow consists of a liquid of small thickness, those instabilities are called Liquid Film Instability or Low Reynolds Instability. Gravitational flows of liquid films are frequently found both in nature and in industry. In nature, some examples are the flows on hills during intense rains and open-channel flows. In industry, some examples are the flows that may occur during painting processes, the application of magnetic tapes, etc., on inclined planes. Under some conditions, longitudinal waves, known as roll-waves, may appear. This project proposes an experimental study of instabilities appearing on the surface of a liquid film flowing by gravity. In order to achieve it, different liquid flows will be controlled and monitored by using microcontrollers. The surface instabilities will be measured by infrared transmissivity, using a device to be developed by the candidate, as well as by digital cameras and automatic post-treatment. From the experiments, we expect to find the wavelengths and the celerities of roll-waves. (AU)