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.

Low-Frequency Velocity Correlation Spectrum of Fluid in a Rectangular Microcapillary

Abstract: In addition to the fast correlation for local stochastic motion, the velocity correlation function in a fluid enclosed within the pore boundaries features a slow long time-tail decay. At late times, the flow approaches that of an incompressible fluid. Here, we consider the motion of a viscous fluid, at constant temperature, in a rectangular semipermeable channel. The fluid is driven through the rectangular capillary by a uniform main pressure gradient. Tiny pressure gradients are allowed perpendicular to the main flux. We solve numerically the three-dimensional Navier-Stokes equations for the velocity field to obtain the steady solution. We then set and solve the Langevin equation for the fluid velocity. We report hydrodynamic fluctuations for the center-line velocity together with the corresponding relaxation times as a function of the size of the observing region and the Reynolds number. The effective diffusion coefficient for the fluid in the microchannel is also estimated (Deff = 1.43 x 10(-10) m2.s-1 for Re = 2), which is in accordance with measurements reported for a similar system (Stepisnik, J.; Callaghan, P. T. Physica B 2000, 292, 296-301; Stepisnik, J.; Callaghan, P. T. Magn. Reson. Imaging 2001, 19, 469-472).

Development of a new method for testing strength of cells against fluid shear stress

Abstract: A new method for testing the strength of cells against fluid shear stress by using a long capillary column was proposed The trajectories of cells in the column were simulated by introducing the Brownian motion model The Brownian motion was performed by the generation of random numbers The mean exposure time to shear stress and the mean shear stress acting on the surface of cells were discussed by the result of computer simulation The mean shear stress acting on the surface of cells flowing in the capillary column was estimated as 4/3-fold of the shear stress at the column wall provided that the ratio of the cell radius to the column radius does not exceed 008 The effectiveness of this new method for testing the strength of cells against fluid shear stress was shown

Flow of a non-Newtonian fluid

Abstract: The objective of the present study is to calculate flows of a non-Newtonian fluid in a plane channel. An exact solution that determines the distribution of the fluid velocity in the transverse cross section of the channel is obtained under certain conditions concerning the dependence of viscosity on the velocity gradient. It is shown that this distribution differs substantially from a parabolic profile of a Newtonian fluid. It is indicated that, in the flow of a non-Newtonian fluid, its special features never disappear-only the region of a non-Newtonian flow shrinks, becoming localized in the vicinity of the velocity maximum.

The Influence of Compressibility on Economic Pipe Diameter for Viscous Flow.

Abstract: Experimental inferences drawn by researchers on fluid flow have indicated the dependence of nature of flow as well as fluid flow parameters in ducts/pipes on the physical properties of fluid. For turbulent flow condition, authors have developed procedures for optimization of conduct size and its dependence on fluid compressibility have been reported. In this work, the iterative optimization procedure for laminar flow in pipeline is reviewed. The resulting optimum function was simulated and validated to generate database for the EXCEL

Characteristics of Shear-Thinning Fluid Flow under Traversal Vibration

Abstract: The effect of vibration on the flow resistance of a shear-thinning fluid was investigated with a newly-designed pressure-scanning capillary viscometer. The experimental apparatus was designed to measure flow resistance continuously over a range of flow rates at a time. Low frequency vibration was applied perpendicularly to the direction of the flow. The effect of the transversal vibration was investigated for both Newtonian fluids and non-Newtonian fluids. The experimental results showed that the vibration had no effect on the flow resistance of the Newtonian fluids. However, the vibration caused a significant reduction of the flow resistance for the shear-thinning fluid. The reduction of the flow resistance was strongly dependent on both vibration frequency and amplitude.