Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
20
4
2017
CHEMICAL REACTION AND RADIATION EFFECTS ON MHD PULSATILE FLOW OF AN OLDROYD-B FLUID IN A POROUS MEDIUM WITH SLIP AND CONVECTIVE BOUNDARY CONDITIONS
The present study investigates the effects of chemical reaction and radiation effects on pulsatile hydromagnetic flow of an Oldroyd-B fluid in a porous medium with slip and convective boundary conditions. Analytical expressions for
velocity, temperature, concentration, Nusselt number, and Sherwood number distributions are obtained. The effects of
different parameters on the dimensionless velocity, temperature, and concentration have been discussed numerically and explained graphically. Analysis indicates that the temperature distribution decreases for a given increase in heat transfer Biot number and Prandtl number, while it increases with an increase in Hartmann number. Further, the concentration distribution decreases with an increase in the Soret number and the heat transfer Biot number, while it decreases for a given increase in the chemical reaction parameter.
T.
Malathy
Muthurangam Government Arts College, Vellore 632002, India
Suripeddi
Srinivas
Department of Mathematics, School of Advanced Sciences, VIT University, Vellore 632014,
India
A. Subramanyam
Reddy
Department of Mathematics, School of Advanced Sciences, VIT University, Vellore 632014,
India
287-301
EQUIVALENT PIPE NETWORK MODEL FOR A COARSE POROUS MEDIA AND ITS APPLICATION TO 2D ANALYSIS OF FLOW THROUGH ROCKFILL STRUCTURES
Development of models for analysis of flow through structures made of coarse porous media such as rockfill dams, breakwaters, sand filters, and gabions has always been a research topic of interest. In this study, the structure of an equivalent pipe network model (EPNM) for analysis of steady two-dimensional (2D) nonlinear free surface flow
through a homogeneous isotropic coarse porous media was investigated. The proposed EPNM consists of orthogonal
pipes where flow through the pipes simulates flow through porous media. Physical and geometrical characteristics of
the EPNM, such as diameter, length, and friction factor of the pipes, are identified according to the porous media
characteristics, e.g., porosity, mean particle size, and friction factor in the turbulent region of flow. A set of available experimental data for two physical models, including a rectangular rockfill structure and a rockfill structure with inclined upstream and downstream faces, was used to verify accuracy of the EPNM. Application of the proposed model in a rockfill structure with an inbuilt spillway was also studied. In this case, the EPNM results were compared with those of a finite element computer code developed in this study for modeling nonlinear flow through dams with inbuilt spillways. The results showed that the EPNM was capable of accurately determining both water surface profile and discharge through rockfill structures. In general, the EPNM, as a new approach for 2D analysis of flow through coarse porous media, employs the methods developed for water distribution network analysis, and as a numerical tool, can model free surface flow through complex rockfill structures such as rockfill dams with inbuilt spillways.
Maryam
Abareshi
Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad,
Iran
Seyed Mahmood
Hosseini
Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad,
Iran
A. Aftabi
Sani
Department of Civil Engineering, Faculty of Engineering, Ferdowsi University of Mashhad,
Iran
303-324
IMPACT OF ECCENTRICITY ON HEAT TRANSFER IN AN ANNULAR SQUARE FILLED WITH SATURATED POROUS MEDIUM
In this work, the eccentricity effect on heat transfer in an annular square filled with a saturated porous medium was
investigated. A numerical solution based on the Galerkin finite element was found for three different cases: (1) positive and negative diagonal eccentricity, (2) positive and negative horizontal eccentricity ±ex, and (3) positive and negative vertical eccentricity. In this study, the outer walls of the annuli were kept isothermally at hot temperature, while the inner walls were kept isothermally at cold temperature. The analysis is carried out to find the influence of eccentricity for three selected nondimensional values (±0.1, ±0.5, ±0.9) on two selected Rayleigh numbers of 100 and 200, without and with the effect of radiation equal to 0 and 1 and for different width ratios (0.25, 0.5, 0.75), respectively. Numerical results of fluid flow and heat transfer characteristics inside the porous medium for the three cases considered were presented and discussed. Furthermore, the results of the average Nusselt number of each outer wall show an increase as eccentricity increases, in particular, at higher values of width ratios ≥0.75.
Munzer S.Y.
Ebaid
Mechanical Engineering Department, Philadelphia University, Amman, Jordan
Laith
Bataresh
Mechanical Engineering Department, Philadelphia University, Amman, Jordan
325-348
FULLY DEVELOPED MIXED CONVECTION IN A NON-DARCY POROUS MEDIUM SATURATED BY A NANOFLUID
This article presents an analytical study of the mixed convection heat transfer in a long channel filled with a porous medium with internal heat generation saturated by a nanofluid. We consider the flow laminar; the vertical walls are kept at a constant temperature while the nanoparticles flux is zero on the vertical walls. The formulation of the problem is based on the Brinkman-Boussinesq approximation using a two-phase nanofluid model. Assuming that the motion is fully developed, a closed-form solution is obtained using symbolic mathematical software. The influence of some effective parameters, such as Reynolds number Re, Lewis number Le, the buoyancy ratio number Nr, the thermophoresis to Brownian motion ratio number NA, Darcy number Da, and Grashof number Gr, on the velocity, temperature, and nanoparticles' concentration profiles is studied. Results for alumina nanoparticles are presented in the form of velocity, temperature, and concentration profiles and values of the average Nusselt number. The maximum values of the dimensionless temperature are predicted for Al2O3 (alumina) and TiO2 (titania) nanoparticles. A theoretical maximum
temperature is obtained for generic nanoparticles possessing very high thermal conductivity.
Radu
Trimbitas
Faculty of Mathematics and Computer Science, Babes-Bolyai University, 400084 Cluj-Napoca,
Romania
Teodor
Grosan
Faculty of Mathematics and Computer Science, Babes-Bolyai University, 400084 Cluj-Napoca,
Romania
349-362
MAGNETOHYDRODYNAMIC EFFECT ON NATURAL CONVECTION IN A CAVITY FILLED WITH A POROUS MEDIUM SATURATED WITH NANOFLUID
Numerical simulation for heat transfer with steady magnetohydrodynamic natural convection cooling of a localized heat source at the bottom wall of an enclosure filled with a porous medium saturated with nanofluids subjected to changeable thermal boundary conditions at the sidewalls has been studied in the presence of an inclined magnetic field. Finite difference method was employed to solve the dimensionless governing equations of the problem. The effects of governing parameters, namely, Hartmann number, solid volume fraction, heat source length, and the locations of the heat source on the streamlines and isotherm contours, as well as maximum temperature, local Nusselt number, and average Nusselt number along the heat source, were considered. The present results are validated by favorable comparisons with previously published results for particular cases. The results of the problem are presented graphically and discussed.
A.M.
Rashad
Department of Mathematics, Aswan University, Faculty of Science, Aswan, 81528, Egypt
Rama Subba Reddy
Gorla
Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, 44115 USA; Department of Mechanical Engineering, University of Akron, Akron, Ohio 44325, USA; Department of Mechanical & Civil Engineering, Purdue University Northwest, Westville, IN 46391, USA
M. A.
Mansour
Department of Mathematics, Assuit University, Faculty of Science, Assuit, Egypt
Sameh Elsayed
Ahmed
Department of Mathematics, Faculty of Science, South Valley University, Qena, Egypt
363-379