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Herschel–Bulkley fluid
About: Herschel–Bulkley fluid is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 49318 citations.
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TL;DR: In this article, a servo-driving system was set-up by assembling a microstepping motor, a ball screw and a linear motion guide for the particle motion in a non-Newtonian fluid.
Abstract: In this research, experimental studies have been performed on the hydrodynamic interaction between a spherical particle and a plane wall by measuring the force between the particle and wall. To approach the system as a resistance problem, a servo-driving system was set-up by assembling a microstepping motor, a ball screw and a linear motion guide for the particle motion. Glycerin and dilute solution of polyacrylamide in glycerin were used as Newtonian and non-Newtonian fluids, respectively. The polymer solution behaves like a Boger fluid when the concentration is 1,000 ppm or less. The experimental results were compared with the asymptotic solution of Stokes equation. The result shows that fluid inertia plays an important role in the particle-wall interaction in Newtonian fluid. This implies that the motion of two particles in suspension is not reversible even in Newtonian fluid. In non-Newtonian fluid, normal stress difference and viscoelasticity play important roles as expected. In the dilute solution weak shear thinning and the migration of polymer molecules in the inhomogeneous flow field also affect the physics of the problem.
5 citations
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TL;DR: Panaseti et al. as mentioned in this paper solved the same problem in a long asymmetric channel with pressure-dependent rheological parameters, where the consistency index and the yield stress are assumed to be pressuredependent.
Abstract: The lubrication flow of a Herschel-Bulkley fluid in a long asymmetric channel, the walls of which are described by two arbitrary functions h1(x) and h2(x) such that h1(x) < h2(x) and h1(x) + h2(x) are linear, is solved extending a recently proposed method, which avoids the lubrication paradox approximating satisfactorily the correct shape of the yield surface at zero order [P. Panaseti et al., “Pressure-driven flow of a Herschel-Bulkley fluid with pressure-dependent rheological parameters,” Phys. Fluids 30, 030701 (2018)]. Both the consistency index and the yield stress are assumed to be pressure-dependent. Under the lubrication approximation, the pressure at zero order is a function of x only, is decoupled from the velocity components, and obeys a first-order integro-differential equation. An interesting feature of the asymmetric flow is that the unyielded core moves not only in the main flow direction but also in the transverse direction. Explicit expressions for the two yield surfaces defining the asymmetric unyielded core are obtained, and the two velocity components in both the yielded and unyielded regions are calculated by means of closed-form expressions in terms of the calculated pressure and the two yield surfaces. The method is applicable in a range of Bingham numbers where the unyielded core extends from the inlet to the outlet plane of the channel. Semi-analytical solutions are derived in the case of an asymmetric channel with h1 = 0 and linearly varying h2. Representative results demonstrating the effects of the Bingham number and the consistency-index and yield-stress growth numbers are discussed.The lubrication flow of a Herschel-Bulkley fluid in a long asymmetric channel, the walls of which are described by two arbitrary functions h1(x) and h2(x) such that h1(x) < h2(x) and h1(x) + h2(x) are linear, is solved extending a recently proposed method, which avoids the lubrication paradox approximating satisfactorily the correct shape of the yield surface at zero order [P. Panaseti et al., “Pressure-driven flow of a Herschel-Bulkley fluid with pressure-dependent rheological parameters,” Phys. Fluids 30, 030701 (2018)]. Both the consistency index and the yield stress are assumed to be pressure-dependent. Under the lubrication approximation, the pressure at zero order is a function of x only, is decoupled from the velocity components, and obeys a first-order integro-differential equation. An interesting feature of the asymmetric flow is that the unyielded core moves not only in the main flow direction but also in the transverse direction. Explicit expressions for the two yield surfaces defining the asym...
5 citations
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TL;DR: Upon fixing the effective viscosity ratio under flow condition, yield-stress and shear-thinning fluids tend to enhance the growth of fingering instability vis-à-vis Newtonian fluid regardless of the flow arrangement, which suggests that the fingering stability is controlled by not only mere modification of the fluid viscosities but also the nature of rheological description of thefluid.
5 citations
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4 citations
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TL;DR: In this article, a layer of nonNewtonian fluid with the theological equation (0.1.2) is loated between two parallel plates and the upper plate moves in the direction of the positive x axis with constant velocity V. The fluid adheres to the wails having the temperatures To and Tt.
Abstract: 1. Flow between two parallel plates. Assume that a layer of nonNewtonian fluid with the theological equation (0.2) is loated between two parallel plates y = h and y = h, and that the upper plate moves in the direction of the positive x axis with constant velocity V. The fluid adheres to the wails having the temperatures To and Tt (T O > T1). The system of equations of motion and heat conduction may be written in dimensionless form
4 citations