AMAL A MADY
Articles written in Pramana – Journal of Physics
Volume 93 Issue 5 November 2019 Article ID 0082 Research Article
A novelty to the nonlinear rotating Rayleigh–Taylor instability
YUSRY O EL-DIB GALAL M MOATIMID AMAL A MADY
This paper presents a novel approach for studying the nonlinear Rayleigh–Taylor instability (RTI). The system deals with two rotating superposed infinite hydromagnetic Darcian flows through porous media under the influence of a uniform tangential magnetic field. The field allows the presence of currents on the surface of separation. The appropriate linear governing equations are solved and confirmed with the corresponding nonlinear boundary conditions. A nonlinear characteristic of the surface deflection is deducted. Away from the traditional techniques of the stability analysis, the work introduces a new one. The analysis depends mainly on the homotopy perturbation method (HPM). To achieve an analytical approximate periodic solution of the surface deflection, the secular terms are removed. This cancellation resulted in well-known amplitude equations. These equations are utilised to achieve stability criteria of the system. Therefore, the stability configuration is exercised in linear aswell as nonlinear approaches. The mathematical procedure adopted here is simple, promising and powerful. The method may be used to treat more complicated nonlinear differential equations that arise in science, physics andengineering applications. A numerical calculation is performed to graph the implication of various parameters on the stability picture. In addition, for more convenience, the surface deflection is depicted.
Volume 95 All articles Published: 9 September 2021 Article ID 0154 Research Article
Nonlinear dynamical analysis of a time-fractional Klein–Gordon equation
YUSRY O EL-DIB NASSER S ELGAZERY AMAL A MADY
In the present work, an enhanced perturbation analysis to solve a time-fractional Klein–Gordon equation (KG equation) and obtain an analytic approximate periodic solution is examined. The Riemann–Liouville fractionalderivative is utilised. A travelling wave solution is adopted throughout the perturbation method by including two small perturbation parameters. The amplitude equation is formulated in the form of a cubic–quintic complexnonlinear Schrödinger equation. The solution of this equation leads to a transcendental frequency equation. An approximate solution to this frequency equation is performed. The stability criteria are derived. The procedure adopted here is very significant and powerful for solving many nonlinear partial differential equations (NLPDEs) arising in nonlinear science and engineering.
Volume 96, 2022
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