Browsing by Author "Singeetham, P.K."

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    Asymptotic solutions of the planar squeeze flow of a casson fluid
    (2018) Singeetham, P.K.; Puttanna, V.K.
    In this study, we present the squeeze flow of viscoplastic fluid using Casson model between parallel plates that are approaching each other with constant squeeze motion. Based on the technique of matched asymptotic expansions, we develop the complete asymptotic solutions for the squeeze flow of viscoplastic Casson fluid model. We derive the expressions for velocity, stress and squeeze force. The effects of the yield threshold on the pseudo-yield surface that separates the sheared and plastic zones and squeeze force for different values of non-dimensional yield stress have been investigated. � 2018 Author(s).
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    Asymptotic solutions of the planar squeeze flow of a casson fluid
    (American Institute of Physics Inc. subs@aip.org, 2018) Singeetham, P.K.; Vishwanath, V.K.
    In this study, we present the squeeze flow of viscoplastic fluid using Casson model between parallel plates that are approaching each other with constant squeeze motion. Based on the technique of matched asymptotic expansions, we develop the complete asymptotic solutions for the squeeze flow of viscoplastic Casson fluid model. We derive the expressions for velocity, stress and squeeze force. The effects of the yield threshold on the pseudo-yield surface that separates the sheared and plastic zones and squeeze force for different values of non-dimensional yield stress have been investigated. © 2018 Author(s).
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    Asymptotic Solutions of the Planar Squeeze Flow of a Herschel-Bulkley Fluid
    (2018) Singeetham, P.K.; Puttanna, V.K.
    In this study, we present the analysis of the squeeze flow of a Herschel-Bulkley fluid between parallel plates that are approaching each other with a constant squeeze motion. The classical lubrication analysis predicts the existence of a central unyielded zone bracketed between near-wall regions. This leads to the well-known squeeze flow paradox for viscoplastic fluids. Since the kinematic arguments show that there must be a finite velocity gradient even in the unyielded zone, thereby precluding the existence of such regions. This paradox may, however, be resolved within the framework of a matched asymptotic expansions approach where one postulates separate expansions within the yielded and apparently unyielded (plastic) zones. Based on the above technique, we circumvent the paradox, and develop complete asymptotic solutions for the squeeze flow of a Herschel-Bulkley fluid. We derive expressions for the velocity, pressure and squeeze force. The effects of the yield threshold on the pseudo-yield surface that separates the sheared and plastic zones, and squeeze force for different values of non-dimensional yield stress have been investigated. � Published under licence by IOP Publishing Ltd.
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    Asymptotic Solutions of the Planar Squeeze Flow of a Herschel-Bulkley Fluid
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Singeetham, P.K.; Vishwanath, V.K.
    In this study, we present the analysis of the squeeze flow of a Herschel-Bulkley fluid between parallel plates that are approaching each other with a constant squeeze motion. The classical lubrication analysis predicts the existence of a central unyielded zone bracketed between near-wall regions. This leads to the well-known squeeze flow paradox for viscoplastic fluids. Since the kinematic arguments show that there must be a finite velocity gradient even in the unyielded zone, thereby precluding the existence of such regions. This paradox may, however, be resolved within the framework of a matched asymptotic expansions approach where one postulates separate expansions within the yielded and apparently unyielded (plastic) zones. Based on the above technique, we circumvent the paradox, and develop complete asymptotic solutions for the squeeze flow of a Herschel-Bulkley fluid. We derive expressions for the velocity, pressure and squeeze force. The effects of the yield threshold on the pseudo-yield surface that separates the sheared and plastic zones, and squeeze force for different values of non-dimensional yield stress have been investigated. © Published under licence by IOP Publishing Ltd.
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    Inertia Effects in the Planar Squeeze Flow of a Bingham Fluid: A Matched Asymptotics Analysis
    (Springer, 2021) Singeetham, P.K.; Vishwanath, V.K.
    The effects of inertia on the squeeze flow of a Bingham fluid between two approaching parallel plates with a constant squeeze velocity is investigated using matched asymptotic expansions. This analysis is an extension to the prior study of Muravleva (2015), who has investigated the planar squeeze flow of a Bingham fluid in the absence of inertia. In the present study, the expressions for the shear stress field, velocity, pressure field and squeeze force are derived. The combined effects of the fluid inertia and yield stress on the pressure field and squeeze force are investigated. We found that the pressure and eventually squeeze force increases with increase in Reynolds number. The squeeze force decreases with an increase in the value of the gap aspect ratio. © 2021, Springer Nature Singapore Pte Ltd.
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    Viscoplastic fluids in 2D plane squeeze flow: A matched asymptotics analysis
    (Elsevier B.V., 2019) Singeetham, P.K.; Vishwanath, V.K.
    A matched asymptotic expansions approach is used to determine the flow behaviour of Casson and Herschel–Bulkley fluids between two parallel plates that are approaching each other with a constant velocity. The present study is based on the earlier work of Muravleva (2015), who has analyzed the squeeze flow of a Bingham fluid using the method of matched asymptotic expansions. A naive application of classical lubrication theory leads to a kinematic inconsistency in the predicted plug region - the well known “squeeze flow paradox” for a viscoplastic fluid. The objective of this work is to determine a consistent solution for the aforementioned constitutive equations. Based on the technique of matched asymptotic expansions, the solution is formulated in terms of separate expansions in the regions adjacent to the two plates where the shear stress is dominant, and a central pseudo-plug (plastic) region where the normal stresses become comparable to the shear stress; the two regions being separated by a pseudo-yield surface. In this manner, a complete asymptotic solution is developed for the squeeze flow of both Casson and Herschel–Bulkley fluid models. Using this solution, we derive expressions for the velocity, pressure and stress fields, and the squeeze force acting to retard the plates. The effect of the yield threshold on the pseudo-yield surface that separates the sheared and plastic zones, pressure distribution and squeeze force is investigated. © 2018 Elsevier B.V.