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This study aims to propose a central composite design (CCD) combined with response surface methodology (RSM) to create a statistical experimental design. A new parametric optimization of entropy generation is presented. The flow behavior of magnetohydrodynamic hybrid nanofluid (HNF) flow through two flat contracting expanding plates of channel alongside radiative heat transmission was considered. The lower fixed plate was externally heated whereas the upper porous plate was cooled by injecting a coolant fluid with a uniform velocity inside the channel. The resulting equations were solved by the Homotopic Analysis Method using MATHEMATICA 10 and Minitab 17.1. The design consists of several input factors, namely a magnetic field parameter ( M ), radiation parameter ( N ) and group parameter ( B r / A 1 ). To obtain the values of flow response parameters, numerical experiments were used. Variables, especially the entropy generation ( N e ), were considered for each combination of design. The resulting RSM empirical model obtained a high coefficient of determination, reaching 99.97% for the entropy generation number ( N e ). These values show an excellent fit of the model to the data. [ABSTRACT FROM AUTHOR]

In this article we propose efficient techniques for solving fractional differential equations such as KdV-Burgers, Kadomtsev-Petviashvili, ZakharovKuznetsov with less computational efforts and high accuracy for both numerical and analytical purposes. The general expa-function method is employed to reckon new exact solitary wave solutions of time fractional nonlinear evolution equations (NLEEs) stemming from mathematical physics. Fractional complex transformation in conjunction with modified Riemann-Liouville operator is used to tackle the fractional sense of the accompanying problems. A comparison with existing conventional exp-function method and improved exp-function method shows that the proposed recipe is more productive in terms of obtaining analytical solutions. The graphical depictions of extracted information show a strong relationship among fractional order outcomes with those of classical ones. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate convective heat and mass transfer of nanofluid in the context of improving physical properties through magnetic and non-magnetic nanomaterials under the magnetic influence. For this, three magnetic nanoparticles: cast iron, pure iron, and magnetite and three non-magnetic: gold, silver, and copper are taken into account. The physical problem for homogenous nanofluid is modeled by employing the magnetic interaction between nanoparticles through Lorentz force into fundamental equations of thermo-hydrodynamic and correlations models that support effective physical properties. The governing equations in dimensionless form are taken to analyse the nanofluid flow as well as heat profile. The impact of interesting physical parameters like particle volume fraction and magnetic field on patterns of velocity and the temperature are graphically demonstrated and discussed. The effect of concentration and size of nanoparticles on shear stress and heat transfer at the wall are examined through numerical values shown in table form. The results show that the heat transfer rate of a base fluid is enhanced by deploying nanoparticles and further improved by taking small-size magnetic nanoparticles. Key words: magnetic and non-magnetic nanoparticles, nanofluid, magnetic force, heat transfer, shape effects. Notre but est d'examiner le transfert convectif de chaleur et de masse de nanofluides dans un cadre visant l'amelioration des proprietes physiques en utilisant des nanofluides magnetiques et non magnetiques sous l'influence de champs magnetiques. A cette fin, nous considerons trois nanofluides magnetiques et trois non magnetiques: fonte, fer pur et magnetique d'une part et or, argent et cuivre d'autre part. La situation physique pour des nanofluides homogenes est modelisee, utilisant une interaction magnetique entre les nanoparticules via une force de Lorentz, en des equations fondamentales de thermo-hydrodynamique et de modeles de correlations qui supportent les proprietes physiques effectives. Nous utilisons les equations directrices sans dimension pour analyser le flot de nanofluide et le profil de chaleur. Nous presentons graphiquement et discutons l'impact des parametres physiques pertinents, comme la fraction volumique de nanoparticules et du champ magnetique sur les patrons de vitesse et de temperature. Les effets de la concentration et de la grosseur des nanoparticules sur la contrainte de cisaillement et le transfert de chaleur au mur sont examines via les resultats numeriques tabules. Les resultats montrent que le taux de transfert de chaleur du fluide de base est ameliore par l'ajout de nanoparticules et encore plus si les nanoparticules sont petites et magnetiques. [Traduit par la Redaction] Mots-cles: nanoparticules magnetiques et non magnetiques, nanofluide, force magnetique, transfert de chaleur, effets dus a la forme., 1. Introduction Conventional heat transfer fluids play a significant role in meeting the increasing demand for heat transfer in industry, such as in heat exchange devices, district cooling, heating systems, [...]

The flow of heat transfer study of carbon nanotubes (CNTs)–water nanofluid over vertical truncated wavy cone is considered. The present boundary layer power law fluid is analyzed near the truncated wavy cone. The considered cone is wavy in physical configuration and placed in a vertical direction. Moreover, nanosized particles of CNTs suspended into water (base fluid) are transporting in two directions, which are modeled by using Boussinesq's approximation. Coordinate transformation is applied in order to shift the wavy surface to a flat surface. Then governing equation dealing with the momentum of nanofluid along with thermal stratification are reduced in dimensionless form by using appropriate transformation. Results point out that the thickness of thermal boundary layer decreases by increasing the value of volume fraction of carbon nanotubes. Finally, the obtained solution is related through a graphical survey, and it is inferred that the investigation is in good accordance with the current literature. [ABSTRACT FROM AUTHOR]