25 research outputs found
The relation of steady evaporating drops fed by an influx and freely evaporating drops
We discuss a thin film evolution equation for a wetting evaporating liquid on
a smooth solid substrate. The model is valid for slowly evaporating small
sessile droplets when thermal effects are insignificant, while wettability and
capillarity play a major role. The model is first employed to study steady
evaporating drops that are fed locally through the substrate. An asymptotic
analysis focuses on the precursor film and the transition region towards the
bulk drop and a numerical continuation of steady drops determines their fully
non-linear profiles.
Following this, we study the time evolution of freely evaporating drops
without influx for several initial drop shapes. As a result we find that drops
initially spread if their initial contact angle is larger than the apparent
contact angle of large steady evaporating drops with influx. Otherwise they
recede right from the beginning
Transport and deposition patterns in drying sessile droplets
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106826/1/aic14338.pd
Basic Procedures and Methodological Support of the “Object-Based Environment for Engineering Calculation in the MATLAB System” Course
This paper looks at methodological aspects of the «Object-based environment for engineering calculation in the MATLAB system» course offered to the second year students of Bauman Moscow State Technical University for mastering tools in the MATLAB environment, learning MATLAB language and object-oriented technology of working with classes and applications, designed for engineering calculations of ammunition characteristics. The paper presents the technology of organization of practical studies using resources of MATLAB Grader
Numerical simulation and stability analysis of solutocapillary effect in ultrathin films
Polar fluids, like water or polydimethylsiloxane, are widely used in technical and medical applications. Capillary effects arising from surface tension gradients can be significant in thin liquid films. The present paper is dedicated to investigation of capillary flow due to a surfactant added to a polar liquid under conditions when intermolecular forces and disjoining pressure play an important role. Evolution equations are formulated for a film profile and the surfactant concentration. Stability analysis shows that the Marangoni effect destabilizes the film, and oscillatory modes appear at slow evaporation rates. We find that the film has four stability modes of at slow evaporation: monotonic stable, monotonic unstable, oscillatory stable, and oscillatory unstable, depending on the wave number of disturbances
Influence of Marangoni instability on evaporation of the polar liquid film
A thin film of an evaporating polar liquid on a solid substrate is investigated within the framework of the lubrication theory. Using linear analysis, we have found that stability of the film depends only on two control parameters: the evaporation and Maranagoni numbers. We demonstrate that the Marangoni effect plays a destabilizing role while evaporation stabilizes the film