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Řešení vývoje nestabilit kapalného filmu s následným odtržením kapek / Modeling of Liquid Film Instabilities with Subsequent Entrainment of Droplets

This dissertation deals with instabilities of thin liquid films up to entrainment of drops. Four types of instabilities have been classified depending on the type of structure and process on the liquid film surface: two-dimensional slow waves, two-dimensional fast waves, three-dimensional waves, solitary waves and entrainment of drops from the film surface. This thesis analyzes the physical principles of instabilities and deals with the mathematical formulation of the problem. Shear and pressure forces acting on the surface of the liquid film are identified as the cause of instabilities. Mathematical models for predicting instabilities are demonstrated using approaches based on solving the Orr-Sommerfeld equation and the equations of motion in integral form. Models of shear and pressure forces acting on the surface of the film and selected models of film thickness are presented. The work is focused on the prediction of the initiation of two-dimensional waves using the integral approach. Shear stress and pressure forces acting on the liquid film surface have been modeled using the simulation of air flow over a solid surface. Finally, criteria for drop entrainment are presented with their dependence on air velocity and film thickness.

Identiferoai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:234165
Date January 2013
CreatorsKnotek, Stanislav
ContributorsKozubková, Milada, Čermák, Libor, Jícha, Miroslav
PublisherVysoké učení technické v Brně. Fakulta strojního inženýrství
Source SetsCzech ETDs
LanguageCzech
Detected LanguageEnglish
Typeinfo:eu-repo/semantics/doctoralThesis
Rightsinfo:eu-repo/semantics/restrictedAccess

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