Ahmed Megahed

Prof. Dr. Ahmed Megahed


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 June 2019 in Journal of the Egyptian Mathematical Society
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Journal Article
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AMAhmed Megahed
Ahmed Megahed
Williamson boundary layer fluid flow and heat transfer due to a nonlinearly stretching sheet is undertaken in this research. An important aspect of this study is that the thermal radiation and viscous dissipation phenomena are also included in this model. Because there is still much need for more accurate results, the viscosity and the fluid conductivity are assumed to vary with temperature. Our main purpose is to achieve a similar solution in this physical model. Here, we come across a highly nonlinear differential constitutive equations which are solved numerically after utilizing the shooting method. In this respect, it is noteworthy that the main characteristic developed here is that the study is made for the governing parameters and their effects on both the drag velocity and the heat transfer rate. Further, a significant effect of both radiation parameter and viscosity parameter on heating process is observed.

23 November 2023 in Heliyon
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Journal Article
Open access
SASara I. Abdelsalam
Sara I. Abdelsalam
WAwael abbas
wael abbas
AMAhmed Megahed
Ahmed Megahed
ASAhmed A.M. Said
Ahmed A.M. Said
The objective of this paper is to examine the flow of a non-Newtonian Maxwell fluid induced by a permeable stretching sheet in motion within a porous medium. The research incorporates the Cattaneo-Christov heat flux model to study the heat transfer process. The utilization of the Cattaneo-Christov heat flux approach becomes relevant in scenarios involving materials with high thermal conductivity or during short time intervals. Consequently, the current investigation holds significant importance. It is assumed that the viscosity of the Maxwell fluid changes exponentially as the temperature changes. The modeling of the physical phenomena being investigated takes into account the effects of a magnetic field, thermal radiation, velocity, and thermal slip conditions. In this study, the viscous dissipation phenomenon is taken into account because it can have notable impacts on the temperature and viscosity of the fluid, and is known to play a crucial role in fluid flow phenomena. The equations developed to model fluid flow are transformed into nonlinear ordinary differential equations through the use of appropriate similarity transformations. The focus of the research revolves around investigating the numerical solution of ordinary differential equations accompanied by boundary conditions using the shooting technique. The findings are then showcased via tables and graphs and scrutinized in order to arrive at conclusions. Furthermore, the precision of the present findings was evaluated by contrasting the heat transfer rate with outcomes that were previously published. Based on the obtained outcomes, it can be concluded that both the Eckert number and thermal radiation have a comparable enhancing influence, whereas the thermal relaxation parameter and thermal slip parameter exhibit opposing effects.

23 December 2021 in Nanotechnology Reviews
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EAElham Alali
Elham Alali
AMAhmed Megahed
Ahmed Megahed
The problem of non-Newtonian Casson thin film flow of an electrically conducting fluid on a horizontal elastic sheet was studied using suitable dimensionless transformations on equations representing the problem. The thin film flow and heat mechanism coupled with mass transfer characteristics are basically governed by the slip velocity, magnetic field, and the dissipation phenomenon. The present numerical analysis by the shooting method was carried out to study the detailed, fully developed heat and mass transfer techniques in the laminar thin film layer by solving the competent controlling equations with eight dominant parameters for the thin liquid film. Additionally, the predicted drag force via skin-friction coefficient and Nusselt and Sherwood numbers were correlated. In view of the present study, a smaller magnetic parameter or a smaller slip velocity parameter exerts very good influence on the development of the liquid film thickness for the non-Newtonian Casson model. Furthermore, a boost in the parameter of unsteadiness causes an increase in both velocity distribution and concentration distribution in thin film layer while an increase in the same parameter causes a reduction in the film thickness. Likewise, the present results are observed to be in an excellent agreement with those offered previously by other authors. Finally, some of the physical parameters in this study, which can serve as improvement factors for heat mass transfer and thermophysical characteristics, make nanofluids premium candidates for important future engineering applications.


1 January 2021 in AIMS Mathematics
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Journal Article
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WAW. Abbas
W. Abbas
AMAhmed Megahed
Ahmed Megahed
The present study explores the effects of viscous dissipation, the thermal dependent conductivity and the thermal dependent viscosity on the steady motion of a Powell-Eyring fluid over a stratified stretching sheet which embedded in a porous medium. The fact that the nature of non-Newtonian flows problems are highly nonlinear equations has been taken into consideration here and this was the motive objective to determine numerical solutions. So, the emphasis is on the methodology adopted for obtaining numerical solutions that yielded after employing the Chebyshev spectral method. The temperature distributions and the velocity components are evaluated by solving numerically the boundary value problems that correspond to the proposed problem. Then, some figures have been plotted to elucidates the effect of different physical parameters appearing in the problem on both the temperature and the velocity profiles. The presence of the thermal radiation and the viscous dissipation in the fluid flow are shown to have quite a dramatic effect on the temperature profiles. In culmination, cooling process in nuclear reactors and geothermal engineering especially in the presence of thermal stratification phenomenon can be adopted as an application of this study. The theoretical and the observed results provide a fairly good qualitative agreement.

10 March 2025 in Modern Physics Letters B
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Journal Article
Closed access
Nourhan I. GhoneimNourhan I. Ghoneim
Nourhan I. Ghoneim
AAAhmed Mohamed Fouad Amer
Ahmed Mohamed Fouad Amer
AMAhmed Megahed
Ahmed Megahed
SASara I. Abdelsalam
Sara I. Abdelsalam