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Prediction of stagnation and minimum pressure points for thin films of power law and Bingham liquids
Author(s) -
Roy S. K.,
Agarwal J. P.
Publication year - 1979
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690250522
Subject(s) - stagnation point , power law fluid , power law , bingham plastic , non newtonian fluid , point (geometry) , newtonian fluid , stagnation pressure , flow (mathematics) , critical point (mathematics) , thermodynamics , mechanics , stagnation temperature , physics , mathematics , geometry , rheology , heat transfer , mach number , statistics
This study concerns the determination of stagnation point and minimum pressure point film thicknesses when a vertical flat plate is withdrawn from a reservoir containing non‐Newtonian liquids. Upon consideration of three types of liquids, namely, Ellis, power law, and Bingham liquids, it has been found that stagnation point or minimum pressure point film thickness is a function of two parameters, one characterizing the liquid and the other representing parallel flow film thickness. It has also been shown that in the case of power law liquids, both the stagnation point and minimum pressure point exist, while in the case of Bingham liquids, the existence of one or both the points for a given nondimensional parallel flow film thickness depends upon the value of the Bingham number. Furthermore, it has been found that there may be situations when both the points can coincide; for example, in the case of Newtonian liquids, the two points coincide if the parallel flow film thickness is \documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt {2 - \sqrt 3 } $\end{document} .