Sufian Munawar

Bio: Sufian Munawar is an academic researcher from University of Dammam. The author has contributed to research in topics: Heat transfer & Nanofluid. The author has an hindex of 12, co-authored 38 publications receiving 489 citations. Previous affiliations of Sufian Munawar include Prince Mohammad bin Fahd University & Quaid-i-Azam University.

Steady flow and heat transfer of a Sisko fluid in annular pipe

Abstract: The flow and heat transfer problem of a Sisko fluid in an annular pipe is considered. The governing nonlinear equation of an incompressible Sisko fluid is modelled. Both analytical and numerical solutions of the governing nonlinear problem are presented. The analytical solutions are developed using homotopy analysis method (HAM) and for the numerical solutions the finite difference method in combination with an iterative scheme is used. A comparison between the analytical and the numerical solutions is presented. Moreover, the shear-thinning and shear-thickening behaviors of the non-Newtonian Sisko fluid are discussed through several graphs and a comparison is also made with the Newtonian fluid.

Three-dimensional squeezing flow in a rotating channel of lower stretching porous wall

Abstract: The present study deals with the three-dimensional flow in a rotating channel of lower permeable stretching wall. The unsteady squeezing flow in the presence of transverse magnetic flux is mathematically modeled with the help of Navier-Stokes equations. The governing equations are normalized with the help of suitable similarity transformations and the analysis is based on a numerical technique. The numerical results are validated with the analytic solution by homotopy analysis method. The flow characteristics are investigated by a comprehensive parametric study. Various aspects of squeezing flow are focused and examined by plotting graphs and tables of stream lines, velocity profiles, pressure gradient and shear stresses. The vertical motion of upper plate interrupts the velocity in the channel remarkably and the pressure variations are significant near the boundaries of the channel. The downward motion of upper plate augments the forward flow and viscous drag on lower plate, whereas, upward motion enhances the reverse flow. However, a suitable choice of squeezing velocity can minimize the viscous drag on lower plate.

Time-Dependent Flow and Heat Transfer over a Stretching Cylinder

Abstract: The unsteady laminar boundary-layer flow and heat transfer of a viscous fluid over a stretching cylinder is discussed in this work. To normalize the governing system of equations a proper set of similarity variables is used. Two types of thermal boundary conditions, prescribed surface temperature (PST) and prescribed heat flux (PHF), are taken into account for thermal analysis. The governing equations are solved using the homotopy analysis method, and the obtained series solution is found to be valid for the entire temporal and spatial domains and for certain ranges of the other physical parameters. The effects of various material parameters on different physical quantities, such as the coefficient of skin friction and the Nusselt number, are illustrated through graphs and tables.

Entropy generation in hydrodynamic slip flow over a vertical plate with convective boundary

Abstract: The present article aims to report the effects of hydrodynamic slip on entropy generation in the boundary layer flow over a vertical sur- face with convective boundary condition. Suitable similarity transformations are used to transform the fundamental equations of hydro- dynamic and thermal boundary layer flow into ordinary differential equations. The governing equations are then solved numerically us- ing the shooting method and the velocity and the temperature profiles are obtained for various values of parameters involved in the gov- erning equations. The expressions for the entropy generation number and the Bejan number are presented and the results are discussed graphically and quantitatively for the slip parameter, the local Grashof number, the Prandtl number, the local convective heat transfer parameter, the group parameter and the local Reynolds number. It is observed that due to the presence of slip, entropy production in a thermal system can be controlled and reduced.

Entropy generation in the Blasius flow under thermal radiation

Abstract: In this work, we examine the effects of thermal radiation and viscous dissipation on entropy generation in the Blasius flow. The governing boundary layer equations for the velocity and temperature fields are transformed into ordinary differential equations with the help of suitable similarity transformation and then solved numerically with the help of the shooting method. The expressions for the volumetric entropy generation rate and the Bejan number are calculated for thermal radiation. The effects of various physical parameters on the entropy production number, average entropy and the Bejan number are studied through graphs using velocity and temperature profiles. It is noticed that by increasing the thermal radiation parameter the entropy production in a thermal system can be reduced and viscous dissipation increases the entropy production.

Entropy generation in steady MHD flow due to a rotating porous disk in a nanofluid

Abstract: We consider the analysis of the second law of thermodynamics applied to an electrically conducting incompressible nanofluid fluid flowing over a porous rotating disk in the presence of an externally applied uniform vertical magnetic field. This study has applications in rotating magneto-hydrodynamic (MHD) energy generators for new space systems and also thermal conversion mechanisms for nuclear propulsion space vehicles. Von Karman transformations are employed to transform the governing equations into a system of nonlinear ordinary differential equations. The entropy generation equation is derived as a function of velocity and temperature gradient. This equation is non-dimensionalized using geometrical and physical flow field-dependent parameters. The velocity profiles in radial, tangential and axial directions, temperature distribution, averaged entropy generation number and Bejan number are obtained. A very good agreement is observed between the obtained results of the current study and those of previously published studies. The effects of physical flow parameters such as magnetic interaction parameter, suction parameter, nanoparticle volume fraction and the type of nanofluid on all fluid velocity components, temperature distribution, averaged entropy generation number and Bejan number, skin friction coefficient and Nusselt number are examined and analyzed and the path for optimizing the entropy is also proposed. In addition, this simulation represents the feasibility of using magnetic rotating disk drives in novel nuclear space propulsion engines and this model has important applications in heat transfer enhancement in renewable energy systems and industrial thermal management.

Physical And Computational Aspects Of Convective Heat Transfer

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A revised model for Darcy-Forchheimer flow of Maxwell nanofluid subject to convective boundary condition

Abstract: This research article provides the magnetohydrodynamic (MHD) boundary-layer flow of Maxwell nanomaterial saturating a non-Darcy porous medium. Flow is generated due to a stretching surface. The flow in porous media is characterized by considering the Darcy–Forchheimer based model. Novel features of Brownian motion and thermophoresis are retained. A uniform applied magnetic field is employed. Small magnetic Reynolds number and boundary-layer assumptions are employed in the formulation. Simultaneous effects of convective heat and zero nanoparticles mass flux conditions are imposed. Transformation procedure is adopted to convert the partial differential system into the nonlinear ordinary differential system. The governing nonlinear ordinary differential system is solved for the convergent homotopic solutions. Convergence analysis is performed through the plot and numerical data. Graphs have been plotted in order to analyze the temperature and concentration profiles by distinct pertinent flow parameters. Local Nusselt number is also computed and examined.

Effects of thermal radiation, viscous and Joule heating on electrical MHD nanofluid with double stratification

Abstract: The investigation is made to study the combined effects of thermal radiation, viscous dissipation and Joule heating in steady two-dimensional electrical magnetohydrodynamic boundary layer flow of nanofluids using Buongiorno's model over a permeable linear stretching sheet. The system of transport equation incorporate the effects of Brownian motion, thermophoresis, thermal and concentration stratifications in the presence of nano energy conversion emerging parameters. A similarity transformation is implemented to reduce the boundary layer flow equations to a system of nonlinear ordinary differential equations, then solved by implicit finite difference scheme. The computation has been investigated for certain range of values required emerging parameters M(0 ≤ M ≤ 2.5), E1(0 ≤ E1 ≤ 1.0), s(−0.4≤s≤1.0), λ(0.1 ≤ λ ≤ 2.0), N(0.1 ≤ N ≤ 1.0), Rd(0 ≤ Rd ≤ 1.0), Nb(0.1 ≤ Nb ≤ 0.5), Nt(0.1 ≤ Nt ≤ 0.5), Ec(0 ≤ Ec ≤ 0.8), st(0 ≤ st ≤ 0.7), Le(2 ≤ Le ≤ 10), sc(0 ≤ sc ≤ 0.7). Velocity field enhances with the electric field and mixed convection but decreases with fluid suction. Electric field resolved the sticking effects due to the magnetic field. Thermal and concentration stratifications lead to a reduction in temperature and nanoparticle concentration. Heat conduction is sensitive to an increase in an electric field, thermal radiation and viscous dissipation. The rate of heat and mass transfer reduces by increasing thermophoresis and thermal stratifications and it increases for larger values of suction. Numerical values are obtained for the skin friction, local Nusselt and Sherwood number for different involving parameters tabulated and examined. We compare the present numerical solution in limiting sense with previously published investigation presented and examined reveals good agreement.