Papers by Dr. Naeem Mustafa
Chemical Engineering Communications, 2007
In this study we investigated the effects of free convection flow of a viscoelastic second-grade ... more In this study we investigated the effects of free convection flow of a viscoelastic second-grade fluid along a vertical flat surface with power-law temperature distribution. The boundary layer equations for the momentum and the energy transport have been reduced to local similarity equations using appropriate transformations. Solutions of the reduced equations are obtained employing the local non-similarity method as well
Abstract: In this paper numerical solutions of a two-phase natural convection dusty fluid flow ar... more Abstract: In this paper numerical solutions of a two-phase natural convection dusty fluid flow are presented. The two-phase particulate suspension is investigated along a vertical cone by keeping variable viscosity and thermal conductivity of the carrier phase. Comprehensive flow formations of the gas and particle phases are given with the aim to predict the behavior of heat transport across the heated cone. The influence of i) air with particles, water with particles and oil with particles are shown on shear stress coefficient and heat transfer coefficient. It is recorded that sufficient increment in heat transport rate can be achieved by loading the dust particles in the air. Further, distribution of velocity and temperature of both the carrier phase and the particle phase are shown graphically for the pure fluid (air, water) as well as for the fluid with particles (air-metal and water-metal particle mixture).
European Physical Journal Plus, 2021
The propagation of cylindrical and spherical (nonplanar) electrostatic ion-acoustic waves (IAWs) ... more The propagation of cylindrical and spherical (nonplanar) electrostatic ion-acoustic waves (IAWs) in a collisionless, unmagnetized, and homogeneous plasma consisting of hot and cold positive ions as well as superthermal electrons are numerically investigated. The nonplanar Korteweg–de Vries (nKdV) equation is deduced from the fluid equations of the plasma species by employing the reductive perturbation technique. For studying the characteristics of the nonplanar electrostatic IAWs, both homotopy perturbation method (HPM) and Adomian decomposition method (ADM) are devoted for solving the nKdV equation numerically. For checking the accuracy of the obtained solutions, a comparison between the exact analytical solution and the approximate numerical solutions of the integrable case (planar KdV equation) is carried out. Moreover, the absolute error and both minimum and maximum residual errors of both ADM and HPM are estimated. Also, the effect of the physical plasma parameters on the chara...
Density functional theory calculations have been performed on Indium nanoclusters (Inn, n= 3 to 1... more Density functional theory calculations have been performed on Indium nanoclusters (Inn, n= 3 to 10) to explore the relative stability among their different isomers and interaction with H2. Geometry optimizations starting from initial candidate geometries were performed for each cluster size, so as to determine a few low energy isomers for each size. Clusters with planar configuration and high symmetry are found to be more stable. For n=8, there comes transition from 2D to 3D structures. Energetically favorable isomers of indium nanoclusters for each size were considered to get H2 adsorbed. In general H2 interaction with these clusters is weak but with those comprising of some odd number of atoms i.e. 5, 7 and 9 is considerable. Indium nanotube also indicates H2 adsorption but Eads increases many folds on introduction of defect in the tube. On the basis of DFT investigations, it is suggested that apparently indium nanoclusters and tubes of specific size seem better candidates for mat...
Chinese Physics Letters, 2016
Magnetosonic shock structures in dissipative magnetized degenerate electron ion plasma are studie... more Magnetosonic shock structures in dissipative magnetized degenerate electron ion plasma are studied. The two fluid quantum magnetohydrodynamic equations for non-degenerate ions and ultra-relativistic degenerate electron fluids with the Maxwell equations are presented. Using the reductive perturbation technique the Korteweg de Vries Burgers (KdVB) equation is derived and its solution is presented with the tanh method. Astrophysical plasma parameters are used to study the effects of variation of plasma density, magnetic field intensity and kinematic viscosity on the propagation characteristics of nonlinear shock structures in such plasma systems.
Astrophysics and Space Science, 2015
In this paper we study the ion acoustic oscillatory and monotonic shocks in dissipative homogeneo... more In this paper we study the ion acoustic oscillatory and monotonic shocks in dissipative homogeneous magnetized plasmas. The dissipation in the plasma system is considered via kinematic viscosity of ions and quantum effects are included through degeneracy pressure of ultra-relativistic electrons. Korteweg de Vries Burgers (KdVB) equation is derived by using reductive perturbation method. Numerical and analytical solutions of KdVB equation are presented. The transition from oscillatory profile to monotonic shock are studied numerically at different values of kinematic viscosity. We also analyzed the effects of variations of different plasma parameters on the strength of the shock structure in dense plasmas. The relevance of the work to astrophysical plasma conditions such as in compact stars is also pointed out.
International Journal of Physical Sciences, 2012
In this paper, the mass transfer in a time varying thin liquid film over a stretching heated plat... more In this paper, the mass transfer in a time varying thin liquid film over a stretching heated plate having variable temperature and concentration is analyzed. The analytical solution for the unsteady Navier-Stokes, energy and diffusion equations are obtained. A new similarity is found using group-theoretic analysis which renders the exact similar governing equations amenable to analytical solution using perturbation method. Numerical solution of the problem is also obtained showing good agreement with analytical results. Graphs of velocity, temperature, concentration, skin-friction, Nusselt number and Sherwood number are displayed for various values of pertinent parameters.
Contributions to Plasma Physics
The characteristics of dust ion-acoustic waves (DIAWs) that are excited because of streaming ions... more The characteristics of dust ion-acoustic waves (DIAWs) that are excited because of streaming ions and hot q-non-extensive electrons obeying a vortex-like distribution are investigated. By exploiting a pseudo-potential technique, we have derived an energy integral equation. The presence of non-extensive q-distributed hot trapped electrons and a streaming ion beam has been shown to influence soliton structure quite significantly. The evolution of the soliton-like perturbations in complex plasmas, taking into account the dissipation processes, are also investigated, obtained by numerically solving the modified Schamel, equation whose widths are dependant on electron trapping efficiency. Our illustrations indicate that compressive DIAWs develop in this plasma. As the plasmas in reality have a relative flow, such an analysis can be used to understand the DIA solitary structures observed in the mesospheric noctilucent clouds. KEYWORDS dissipative solitons, dust ion acoustic solitons, electron trapping 1 INTRODUCTION An ionized gas (either fully or partially) laden with heavier charged particles is defined as dusty plasma. These heavier charged particles with a mass in the micron or submicron range are called dust particles or grains. [1] Dust-containing plasmas can be found anywhere, including plasmas in laboratories, near the earth, in the environments of planets, interplanetary space, cometary tails, interstellar clouds, mesospheric noctilucent clouds, rings of giant planets (e.g., Saturn's F rings), and various Earth-bound plasmas. [2,3] These dust particles make analysis more difficult as it requires additional coordinates of space and time. [4,5] Langmuir et al. [6] carried out a theoretical investigation to study the impact of dust particles on plasma characteristics. Later, their findings (or conclusions) were confirmed experimentally. [7,8] These dust particles can have a negative or positive charge on it, depending on which ionization or excitation processes are dominant in the dusty plasma environments. [9,10] Owing to lighter mass, the electrons are more mobile compared to ions, and hence, they (electrons) have a greater chance to become attached to comparatively heavier dust. They (electrons) attach to the dust particle's surfaces in large quantity, making these particles' charge frequently negative in experiments of laboratories as well as in space environments observed in nature. However, in the case of dominant secondary electron production and photoionization, these dust particles may acquire positive charge, but negatively charged dust is prevalent in dusty plasmas of laboratories at low temperatures. [11] The existence of such heavier species can give rise to various types of collective processes, which consequently help the plasma sustain some new, very low-frequency modes. The dust ion-acoustic (DIA) mode is one of these novel modes that can develop in unmagnetized dust plasmas. Under the equilibrium quasi-neutrality condition, that is, n e0 + n d0 Z d = n i0 for n e0 ≪ n i0 , a dusty plasma can sustain low-frequency DIA waves. [12] Here, n d0 , n i0 , and n e0 represent the number densities of dusty particles, ions, and electrons, respectively. The DIAWs' phase speed is much higher/lower than the thermal speeds of ions/electrons. For longer wavelengths, the DIA waves' dispersion relations become analogous to the ion-acoustic (IA) waves' dispersion relation,
Heat and Mass Transfer, 2016
In this paper numerical solutions of a two-phase natural convection dusty fluid flow are presente... more In this paper numerical solutions of a two-phase natural convection dusty fluid flow are presented. The two-phase particulate suspension is investigated along a vertical cone by keeping variable viscosity and thermal conductivity of the carrier phase. Comprehensive flow formations of the gas and particle phases are given with the aim to predict the behavior of heat transport across the heated cone. The influence of i) air with particles, water with particles and oil with particles are shown on shear stress coefficient and heat transfer coefficient. It is recorded that sufficient increment in heat transport rate can be achieved by loading the dust particles in the air. Further, distribution of velocity and temperature of both the carrier phase and the particle phase are shown graphically for the pure fluid (air, water) as well as for the fluid with particles (air-metal and water-metal particle mixture).
International Journal for Numerical Methods in Fluids, 2012
... Naeem Mustafa1,∗,, S. Asghar1 and T. Hayat2,3 ... He's homotopy ∗Correspondence to:Naee... more ... Naeem Mustafa1,∗,, S. Asghar1 and T. Hayat2,3 ... He's homotopy ∗Correspondence to:Naeem Mustafa, Department of Mathematics, COMSATS Institute of Information Technology, Islamabad, Pakistan. E-mail: [email protected] ...
International Journal for Numerical Methods in Fluids, 2012
... Naeem Mustafa1,∗,, S. Asghar1 and T. Hayat2,3 ... He's homotopy ∗Correspondence to:Naee... more ... Naeem Mustafa1,∗,, S. Asghar1 and T. Hayat2,3 ... He's homotopy ∗Correspondence to:Naeem Mustafa, Department of Mathematics, COMSATS Institute of Information Technology, Islamabad, Pakistan. E-mail: [email protected] ...
International Journal for Numerical Methods in Fluids, 2012
... Naeem Mustafa1,∗,, S. Asghar1 and T. Hayat2,3 ... He's homotopy ∗Correspondence to:Naee... more ... Naeem Mustafa1,∗,, S. Asghar1 and T. Hayat2,3 ... He's homotopy ∗Correspondence to:Naeem Mustafa, Department of Mathematics, COMSATS Institute of Information Technology, Islamabad, Pakistan. E-mail: [email protected] ...
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Papers by Dr. Naeem Mustafa