Journal ArticleDOI
Asymptotic study of film thinning process on a spinning annular disk
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TLDR
In this paper, an axisymmetric flow of a thin liquid film on a rotating annular disk is considered, and an asymptotic solution for the free surface of the thin film is found using an expansion for the film thickness in powers of a small parameter characterizing the thickness in comparison to the inner disk radius.Abstract:
We consider an axisymmetric flow of a thin liquid film on a rotating annular disk. The effects of surface tension and gravity terms are included. An asymptotic solution for the free surface of the thin film is found using an expansion for the film thickness in powers of a small parameter characterizing the film thickness in comparison to the inner disk radius, and then applying the method of matched asymptotic expansion. The asymptotic solution is capable of predicting several features of spin-coating processes. For example, we find that the surface tension enhances film thinning at the central region whereas the gravity does not. The results show that the final film thickness does not depend on the initial distribution of the film thickness (be it uniform or nonuniform) and on the initial amount of liquid deposited. We find that most of the liquid initially deposited on the disk flows out of the disk in a very short time at the initial stages of spinning, regardless of the type of initial distribution of the film thickness. The retention of fluid for nonuniform initial distribution is more than that for uniform distribution at the early stages of the spreading of the thin film.read more
Citations
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Journal ArticleDOI
Flow of a thin liquid film on an unsteady stretching sheet
B.S. Dandapat,S. Maity +1 more
TL;DR: In this article, it is shown that the final film thickness is independent of the amount of liquid distributed initially and on the initial film thickness be it uniform or non-uniform.
Journal ArticleDOI
Controlling nanomaterial synthesis, chemical reactions and self assembly in dynamic thin films
TL;DR: The spinning disc processor (SDP) and the related rotating tube processor (RTP), are highlighted in the use of highly sheared and micro-mixed dynamic thin films in gaining control over such processing for a wide range of applications.
Journal ArticleDOI
Transient film profile of thin liquid film flow on a stretching surface
TL;DR: In this paper, a non-planar thin liquid film flow on a planar stretching surface is considered and the effect of inertia of the liquid is considered, and equations describing the laminar flow on the stretching surface are solved analytically.
Journal ArticleDOI
Unsteady two-layer film flow on a non-uniform rotating disk in presence of uniform transverse magnetic field
B.S. Dandapat,S.K. Singh +1 more
TL;DR: Two-layer film flow over a non-uniformly rotating disk in presence of uniform transverse magnetic field is studied numerically under the assumption of planar interface and it is found that the lower layer thins faster than the upper layer at the initial stage, later on, upper layer thin faster in all three different type of rotations.
Journal ArticleDOI
The thickening effect of interfacial surfactant in the drag-out coating problem
Prabir Daripa,Gelu Paşa +1 more
TL;DR: In this paper, it was shown that the film thickens in the presence of interfacial surfactant for low capillary numbers if surface tension away from the transition and meniscus regions increases in the direction of withdrawal of the plate, a condition that should truly emerge from the solution of the full problem.
References
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Journal ArticleDOI
Flow of a Viscous Liquid on a Rotating Disk
TL;DR: In this paper, it was shown that initially irregular fluid distributions tend toward uniformity under centrifugation, and means of computing times required to produce uniform layers of given thickness at given angular velocity and fluid viscosity are demonstrated.
Journal ArticleDOI
Characteristics of resist films produced by spinning
TL;DR: In this article, a model for the description of thin films prepared from solution by spinning is presented, and the thickness of the film and the time of drying can be calculated as functions of various processing parameters.
Journal ArticleDOI
Fingering Instabilities of Driven Spreading Films
TL;DR: In this article, it was shown that a thin film with small dynamic contact angle and driven by an external body force is unstable to the formation of fingers in the direction perpendicular to the main flow.
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