Abstract
Purpose
This paper aims to assess the effectiveness of Hall currents and power-law slip condition on the hydromagnetic convective flow of an electrically conducting power-law fluid over an exponentially stretching sheet under the effect of a strong variable magnetic field and thermal radiation. Flow formation is developed using the rheological expression of a power-law fluid.
Design/methodology/approach
The nonlinear partial differential equations describing the flow are transformed into the nonlinear ordinary differential equations by employing the local similarity transformations and then solved numerically by an effective numerical approach, namely, fourth-order Runge–Kutta integration scheme, along with the shooting iteration technique. The numerical solution is computed for different parameters by using the computational software MATLAB bvp4c. The bvp4c function uses the finite difference code as the default. This method is a fourth-order collocation method. The impacts of thermophysical parameters on velocity and temperature distributions, skin friction coefficients and Nusselt number in the boundary layer regime are exhibited through graphs and tables and deliberated with proper physical justification.
Findings
Our investigation conveys that Hall current has an enhancing behavior on velocity profiles and reduces skin friction coefficients. An increase in the power-law index is observed to deplete velocity and temperature evolution. The temperature for the pseudo-plastic (shear-thinning) fluid is relatively higher than the corresponding temperature of the dilatant (shear-thickening) fluid. The streamlines are more distorted and have low intensity near the surface of the sheet for the dilatant fluid than the pseudo-plastic fluid.
Social implications
The study is pertinent to the expulsion of polymer sheet and photographic films, hydrometallurgical industry, electrically conducting polymer dynamics, magnetic material processing, solutions and melts of polymer processing, purification of molten metals from nonmetallic. The results obtained in this work can be relevant in fluid mechanics and heat transfer applications.
Originality/value
The present problem has, to the authors' knowledge, not communicated thus far in the scientific literature. A comparative study with the published works is conducted to verify the accuracy of the present study. The results obtained in this analysis are significant in providing the standards for validating the accuracies of some numerical or empirical methods.
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Mohamed Almakki, Hiranmoy Mondal and Precious Sibanda
This paper aims to investigate entropy generation in an incompressible magneto-micropolar nanofluid flow over a nonlinear stretching sheet. The flow is subjected to thermal…
Abstract
Purpose
This paper aims to investigate entropy generation in an incompressible magneto-micropolar nanofluid flow over a nonlinear stretching sheet. The flow is subjected to thermal radiation and viscous dissipation. The energy equation is extended by considering the impact of the Joule heating term because of an imposed magnetic field.
Design/methodology/approach
The flow, heat and mass transfer model are solved numerically using the spectral quasilinearization method. An analysis of the performance of this method is given.
Findings
It is found that the method is robust, converges fast and gives good accuracy. In terms of the physically significant results, the authors show that the irreversibility caused by the thermal diffusion the dominants other sources of entropy generation and the surface contributes significantly to the total irreversibility.
Originality/value
The flow is subjected to a combination of a buoyancy force, viscous dissipation, Joule heating and thermal radiation. The flow equations are solved numerically using the spectral quasiliearization method. The impact of a range of physical and chemical parameters on entropy generation, velocity, angular velocity, temperature and concentration profiles are determined. The current results may help in industrial applicants. The present problem has not been considered elsewhere.
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Amal Mohamed El-Moursy, Zeinab Mohmed Abdel Mageid, Manar Yahia Ismail Abd El-Aziz, Nour Asser and Osama Hakeim
Wearing clothes requires specifications for feeling comfortable, derived from the fibres, fabrics and finishing properties. This study aims to deal with the effect of economic…
Abstract
Purpose
Wearing clothes requires specifications for feeling comfortable, derived from the fibres, fabrics and finishing properties. This study aims to deal with the effect of economic blends containing hollow fibres, bamboo and cotton/polyester waste on the mechanical properties of the produced fabrics and the appropriate end use.
Design/methodology/approach
This research included two blends: one consisted of cotton/polyester wastes blended with bamboo and the other to which Chorisia fibres were added. Two weft counts 10,6/1 Ne were made from each blend, which were used to produce four fabric samples (S1 Chorisia-free and S2 with Chorisia); additionally, another two samples were dyed that contain Chorisia (S3) from each count. The six samples were tested by Kawabata Evaluation System (KES).
Findings
The samples gave a good total hand value (THV) for use as men's winter suits, where the thicker count 6/1, with and without Chorisia had better properties, also both counts 6, 10/1 with dye. The hollow fibres affected the fabrics’ properties, including thickness, shear, bending, thermal conductivity and weight. Both blends had a positive effect on THV.
Research limitations/implications
Cotton/polyester waste, Chorisia and bamboo fibres were tested, and 2% Remazol Yellow GNL dye was used.
Practical implications
The ratio of blending, weft counts and dye affected the fabric’s properties, with consequences for the use of the Kawabata system and its applications.
Social implications
The fabrics used in this research may be considered to be economical and have good THV.
Originality/value
The study proved the usefulness of fabrics made of two blends. The Chorisia component may be seen as a good alternative to cotton fibres to reduce the cost of producing high-consumption winter suit fabrics.
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Heba Tolla El Sayed Abo El Naga and Manar Yahia Ismail Abd El-Aziz
Synthetic materials have many drawbacks in high-performance garments because they absorb less moisture and cause allergies to sensitive individuals. Cotton materials cannot…
Abstract
Purpose
Synthetic materials have many drawbacks in high-performance garments because they absorb less moisture and cause allergies to sensitive individuals. Cotton materials cannot satisfy all the requirements and cannot provide the required high performance. This study aims to use eco-friendly materials with a common structure to analyse their suitability for high-performance garment application.
Design/methodology/approach
This study used two eco-friendly yarns (bamboo, modal and bamboo: modal 50:50) and yarns per needle (two- and four-ply yarns). with a single jersey knit construction and gauge of 7. The physical, mechanical, appearance, comfort, thermal and ultraviolet protection factor (UPF) protection characteristics were evaluated using 15 tests.
Findings
The produced knitted fabrics showed high performance for use as garments with physical, mechanical, appearance, comfort, thermal and UPF protection characteristics that were achieved, tested and analysed. The highest-achieved samples with a good UPF (>15) were made from bamboo material, which has other high-performance characteristics such as antibacterial characteristics, a soft surface, thermal insulation and others.
Research limitations/implications
The single jersey structure was used for producing fabrics as it is the common structure in the garment. Also, only gauge 7 was used for its economics and ease of production.
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A.A. El Warraky, A.M. El‐Aziz and Kh.A. Soliman
The paper aims to study the dissolution of Al, Al‐3.84%Cu, Al‐5.22%Cu and Al‐11%Cu alloys in different concentrations of NaCl (10‐5‐10‐1 M).
Abstract
Purpose
The paper aims to study the dissolution of Al, Al‐3.84%Cu, Al‐5.22%Cu and Al‐11%Cu alloys in different concentrations of NaCl (10‐5‐10‐1 M).
Design/methodology/approach
The approach is to use open circuit potential (OCP) and potentiostatic polarization measurements.
Findings
Results obtained showed that, as the Cu content was increased in the Al‐Cu alloys, a steady state potential was rapidly reached. Addition of different concentrations of CuCl2 to 0.5 M NaCl demonstrated that by increasing the concentration of CuCl2 up to 2 ppm a greater increase in the OCP towards more anodic value occurred from the moment of immersion. Further increases in the concentration of CuCl2, up to 600 ppm, exhibited the same behavior.
Originality/value
The results of the study reveal that cathodic current was controlled by the oxygen in solution, while the anodic current increased with increased Cu content in the alloy.
A.A. El Warraky, A.M. El‐Aziz and Kh.A. Soliman
The paper aims to examine the enrichment of Cu, and the type of attack occurring during the dissolution of Al‐3.84%Cu alloy in 0.5 M NaCl.
Abstract
Purpose
The paper aims to examine the enrichment of Cu, and the type of attack occurring during the dissolution of Al‐3.84%Cu alloy in 0.5 M NaCl.
Design/methodology/approach
The approach is to use scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDX) and solution analyses using atomic absorption spectrophotometry.
Findings
Examination of the surface after five days of immersion showed that Cu clusters had concentrated around the edges of the specimens and two types of localized corrosion were evident, pitting corrosion and the intergranular attack, which were concentrated mainly around the Cu clusters and in the regions where a higher concentration of Cu was evident. After 80 days of immersion, the higher concentration of Cu was distributed over nearly the entire surface and its concentration differed from one site to another.
Originality/value
The analysis results of the study confirmed the mechanism of simultaneous dissolution.
Mohammad Madani, Yasir Khan, Mahdi Fathizadeh and Ahmet Yildirim
The purpose of this paper is to report the effect of radiation on flow of a magneto‐micropolar fluid past a continuously moving plate with suction and blowing.
Abstract
Purpose
The purpose of this paper is to report the effect of radiation on flow of a magneto‐micropolar fluid past a continuously moving plate with suction and blowing.
Design/methodology/approach
The governing equations are transformed into dimensionless nonlinear ordinary differential equations by similarity transformation. Analytical technique, namely the homotopy perturbation method (HPM) combining with Padé approximants and finite difference method, are used to solve dimensionless non‐linear ordinary differential equations. The skin friction coefficient and local Nusselt numbers are also calculated. Beside this, the comparison of the analytical solution with numerical solution is illustrated by the graphs for different values of dimensionless pertinent parameters.
Findings
The authors have studied laminar magneto‐micropolar flow in the presence of radiation by using HPM‐Padé and finite difference methods. Results obtained by HPM‐Padé are in excellent agreement with the results of numerical solution.
Originality/value
The HPM‐Padé is used in a direct way without using linearization, discritization or restrictive assumption. The authors have attempted to show the capabilities and wide‐range applications of the HPM‐Padé in comparison with the finite difference solution of magneto‐micropolar flow in the presence of radiation problem.
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P.K. Kameswaran, Z.G. Makukula, P. Sibanda, S.S. Motsa and P.V.S.N. Murthy
The purpose of this paper is to study heat and mass transfer in copper-water and silver-water nanofluid flow over stretching sheet placed in saturated porous medium with internal…
Abstract
Purpose
The purpose of this paper is to study heat and mass transfer in copper-water and silver-water nanofluid flow over stretching sheet placed in saturated porous medium with internal heat generation or absorption. The authors further introduce a new algorithm for solving heat transfer problems in fluid mechanics. The model used for the nanofluid incorporates the nanoparticle volume fraction parameter and a consideration of the chemical reaction effects among other features.
Design/methodology/approach
The partial differential equations for heat and mass transfer in copper-water and silver-water nanofluid flow over stretching sheet were transformed into a system of nonlinear ordinary differential equations. Exact solutions for the boundary layer equations were obtained in terms of a confluent hypergeometric series. A novel spectral relaxation method (SRM) is used to obtain numerical approximations of the governing differential equations. The exact solutions are used to test the convergence and accuracy of the SRM.
Findings
Results were obtained for the fluid properties as well as the skin friction, and the heat and mass transfer rates. The results are compared with limiting cases from previous studies and they show that the proposed technique is an efficient numerical algorithm with assured convergence that serves as an alternative to numerical methods for solving nonlinear boundary value problems.
Originality/value
A new algorithm is used for the first time in this paper. In addition, new exact solutions for the energy and mass transport equations have been obtained in terms of a confluent hypergeometric series.
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Prabhugouda Mallanagouda Patil, Geeta Hadimani, Shashikant A., P.S. Kulkarni and Mukesh Kumar
This paper aims to provide a detailed study on the influence of slip flow and thermal jump over mixed convection flow along an exponentially stretching surface. Also, impacts of…
Abstract
Purpose
This paper aims to provide a detailed study on the influence of slip flow and thermal jump over mixed convection flow along an exponentially stretching surface. Also, impacts of suction/blowing, volumetric heat source/sink and velocity ratio parameter will be studied in this analysis.
Design/methodology/approach
The modeled governing equations for the assumed problem are dimensional nonlinear partial differential equations in nature. To reduce these equations, non-similar transformations are used to get the dimensionless nonlinear partial differential equations. Then, quasi-linearization technique is used to linearize these non-dimensional nonlinear partial differential equations. Finally, an implicit finite difference scheme is used to discretize the resulting equations.
Findings
The physical explanations are provided for the variations of various non-dimensional governing parameters over the velocity and temperature profiles. Also, the effects of these dimensionless parameters on skin friction coefficient and heat transfer rate are scrutinized in a manner which highlights their physical interpretation. The detailed discussion exhibits the fact that the streamwise co-ordinate velocity ratio parameter, partial slip parameter and the thermal jump parameter have significant influence over the flow and thermal fields.
Originality/value
This work has not been reported in the literature to the authors’ best of knowledge.
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Prabhugouda Mallanagouda Patil, Nafisabanu Kumbarwadi and Shashikant A.
The purpose of this paper is to investigate the magnetohydrodynamics mixed convection flow over an exponentially stretching surface in the presence of non-uniform heat source/sink…
Abstract
Purpose
The purpose of this paper is to investigate the magnetohydrodynamics mixed convection flow over an exponentially stretching surface in the presence of non-uniform heat source/sink and cross-diffusion. Adequate non-similar transformations are used to transform governing mixed convection boundary layer equations to dimensionless form.
Design/methodology/approach
These dimensionless partial differential equations are solved by using implicit finite difference scheme in conjunction with Quasi-linearization technique.
Findings
The effects of admissible parameters such as Eckert number (Ec), the ratio of buoyancy forces parameter (N), non-uniform heat source/sink, Soret and Dufour numbers on flow, temperature and concentration distributions are discussed and analysed through graphs. In addition, the results for skin friction coefficient, Sherwood number and Nusselt number are presented and discussed graphically.
Originality/value
In literature, no research work has been found in similar to this research paper.