Search

The significance of peristaltic phenomena has generated substantial interest within the fields of biological and biomedical engineering. Therefore, the present study deals with magnetohydrodynamics (MHD) peristaltic flow of Bingham nanofluid in a channel. Here the channel walls are symmetric and elastic in nature. Velocity slip, heat and mass convective conditions are enforced on channel walls. The aspects of dissipation, Joule heating and mixed convection is analyzed. Thermal transport included the features of thermal radiation, Brownian and thermophoresis motion. Analysis and modelling are investigated in the presence of the phenomenon heat generation and absorption. The analysis has been wrapped up under the assumptions of a long wavelength and a low Reynolds number. Numerical techniques are implemented for finding the solutions of governing differential system. Results for velocity, concentration, thermal field, rate of heat transfer, skin friction coefficient, Nusselt number and Sherwood number are analyzed subject to pertinent parameters. The study reveals that velocity is enhanced via both thermal Grashof number and velocity slip parameter. Temperature shows opposite behavior against radiation and Brinkman number. Rate of heat transfer enhances for larger values Brownian motion and Hartman parameters. This study's practical applications include the use of peristaltic pumps for drug delivery in the pharmaceutical and chemical industries. [Display omitted] • Peristaltic flow of MHD Bingham nanofluid in a channel is modeled. • Heat generation/absorption and viscous dissipation effects are considered. • Elastic properties of the channel walls are considered. • Effects of mixed convection and convective conditions are also taken into account. • Numerical technique is implemented for the solutions of resulting systems of equations. [ABSTRACT FROM AUTHOR]

To give a simpler theoretical solving approach for modeling the grouting process of viscous slurry in porous/broken rocks, this work derives two theoretical spatiotemporal distribution equations of viscous slurry penetration in rock fissures based on the Darcy seepage model (DM) and the Bingham fluid model (BM) through a hypothetical micro-element model. Through a two-dimensional (2D) conceptual grouting hole model with porous media, the applicability of the two proposed theoretical spatiotemporal distribution equations of viscous slurry pressure is validated by comparing the analytical results with the numerical results obtained from the two-phase flow simulation. The results indicate that the analysis results obtained from two proposed theoretical spatiotemporal distribution equations are well consistent with the simulation results at different times and under different grouting velocities. That means the time-consuming numerical simulation of the porous/broken rocks grouting process can be replaced by two proposed theoretical spatiotemporal distribution equations, which will greatly reduce the difficulty of real-time evaluation of the grouting effects in engineering practice and shorten the assessment time. • Two theoretical spatiotemporal distribution equations of viscous slurry penetration in rock fissures are derived. • Applicability of the two proposed theoretical spatiotemporal distribution equations is validated. • Grouting pressure at the grouting hole increases linearly with the increase of grouting velocity. [ABSTRACT FROM AUTHOR]

The rheological behaviors of highly concentrated fine particle suspensions (clay-silt-water mixtures) and coarse particle suspensions (coarse particles within a fine particle suspension) were investigated in this study. Experimental results demonstrated that the Bingham Fluid Model with two rheological parameters, Bingham yield stress and viscosity, well characterized the rheological behavior of fine particle suspensions at shear rates between 4 and 20 s−1. The inclusion of coarse particles within a fine particle suspension induced an enhancement to the rheological parameters. The rheological parameters of a coarse particle suspension not only depend on its total particle fraction but also on its relative fine/coarse particle fractions. Empirical equations of these two parameters were proposed, quantitatively related to both fine and coarse particle fractions. Results indicated that the Bingham yield stress and viscosity are much more (an order larger) sensitive to changes in fine particle fraction than to changes in coarse particle fraction. [ABSTRACT FROM AUTHOR]

In this paper, laminar flow of non-Newtonian (Bingham) fluid is studied numerically in a two-dimensional lid-driven skewed cavity that incorporates Papanastasiou exponential regularization approach of Bingham constitutive model [Papanastasiou, Flows of materials with yield, J. Rheol. 31 (1987), pp. 385–404]. Numerical simulation has been done using the finite-volume method with collocated grid arrangement. The governing equations including continuity and momentum are initially non-dimensionalized using appropriate transformation. To simulate irregular shape cavity flow problem, body-fitted non-orthogonal grids are used, and governing equations have been transformed to generalized curvilinear co-ordinates. In this study, two dimensionless parameters namely, Reynolds number and Bingham number are considered. A wide range of skew angles are considered which comprises both acute and obtuse angles. The obtained results are presented in terms of velocity and streamlines with yielded/unyielded region for different values of Bingham number and Reynolds number having different angles of the skewed cavity. The present results may be serve as benchmark results for comparison purpose in the case of non-Newtonian (Bingham) fluid flow. [ABSTRACT FROM AUTHOR]

Rock grouting has been extensively adopted to be a suitable method applied to seepage prevention and consolidation in discrete dam foundations. However，when constructed in fissured for^nations comprising unconsolidated earth and rock masses，practical problems，for ex­ample leakage in borehole sealing，borehole splitting repeatedly at low pressure，and unstable grouting pressure have often been raised and hindered future application of this technique. This study intended to explain the features of grout mixes in borehole blocking，on the bases of fracturing failure model of borehole sealant，mechanism of grouting slurry blocking，and the relationships between grouting mixes and bore­hole sealing effect. It is suggested that yielding strengths of grouting mixes， widths of fissures， rheological properties and depths of sealant mi­xes dominate multitudes and lasting time of splitting pressure. In the meantime， our study also proposed that the splitting pressure of borehole sealant has a close relationship with the cohesion of the mix and develops with yielding strength increment of grouting mix. The splitting pres­sure of a mix tends to decrease with the increase of fissure width. The tendency aggravates with the depth increase of borehole sealant. Impro­ving sealant yielding strength obtains appropriate effect of fissure width reduction. Furthermore， increasing concentration of grouting mixes generates larger viscosity and yielding strength， which is effective in assuring the action of borehole blocking. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tokyo Bay is one of the estuaries in Japan with a high population of almost 26 million people in the basin area. One of the major concerns for the environment in this water area is the decreasing ecosystem functions including the deterioration of water and sediment qualities caused by various anthropogenic activities. Since the bottom sediments around almost the entire area of the inner bay consist of fine materials with a high organic content, which cause the deterioration of water quality through processes such as hypoxia, an understanding of the fine sediment dynamics in the Bay is crucial for an environmental assessment of the water area. This paper proposes a model for the key processes of fine sediment dynamics, which reflects field data about muddy bed structures and their dynamics obtained during the monitoring campaign in 2007. One of the specific features of the sediment in the Bay at present is the persistent existence of fluid mud layers (water content over 300 %) with a thickness of around a few decimeters, which might be caused by deposition of abundant organic particles due to eutrophication. The present study shows that diffusion flux model delivers quite reliable results for estimating erosion flux from the top of fluid mud layers after calibrating the model parameter against the time series data of vertical flux measured by an acoustic Doppler velocimeter system. This study also derives analytical solutions, based on the Bingham fluid concept, of advection flux in the fluid mud layer on which external shear stress force is applied. [ABSTRACT FROM AUTHOR]