Articles written in Pramana – Journal of Physics
Volume 96 All articles Published: 3 February 2022 Article ID 0040 Research Article
Heat transfer enhancement in a power-law nanofluid flow between two rotating stretchable disks
USMAN ABUZAR GHAFFARI TASEER MUHAMMAD IRFAN MUSTAFA
The advanced thermal characteristics of nanomaterials allow better heat transfer efficiency in engineering, industrial and technological processes. In this report, the outcome of a comparative analysis between the dynamics of blood carrying Cu nanoparticles and blood carrying single-walled carbon nanotubes (SWCNTs) due to the stretching and rotation of two disks at various levels of rotation, stretching, power-law index and heat source/sink is presented. By using appropriate similarity variables, the leading partial differential equations (PDEs)are altered into one-dimensional equations (ODEs). The resulting ODEs are handled using the shooting method. The impact of governing parameters on the boundary layer profiles is analysed graphically. Fluid velocity gets enhanced in three dimensions during the rotation of the disk, but they predict different behaviours for the stretching parameters of the upper and lower disks. The temperature decays for power-law index, rotation and stretching parameters. Also,the rates of heat transfer are more extensive for shear-thinning. Finally, the effects of the Cu–blood(blood) nanofluid are dominant over the base fluid (blood) and SWCNTs–blood nanofluid.
Volume 96 All articles Published: 16 March 2022 Article ID 0058 Research Article
Heat and mass transfer features of transient second-grade fluid flow through an exponentially stretching surface
AAMIR ABBAS KHAN MUHAMMAD NAVEED KHAN NAVEED AHSAN M IJAZ KHAN TASEER MUHAMMAD AYESHA REHMAN
This paper deals with an unsteady magnetohydrodynamic (MHD) two-dimensional (2D) second-grade fluid flow towards a permeable exponentially stretching surface with homogeneous–heterogeneous reactions. The non-uniform heat source/sink, variable thermal conductivity and thermal radiation are considered to analyse the thermal attributes. The velocity slip effect is also taken into consideration at the boundary of the surface. The modelled equations of motions and energy are transformed into non-linear ODEs by suitable transformations. The Matlab Bvp4c approach is employed for the numerical solution of the equations. The impacts of various parameters are scrutinised using graphs. The physical quantities of interests such as Sherwood number,Nusselt number and skin friction are presented in the form of graphs and tables and discussed. The velocity profile diminishes by enhancing the values of the parameter of the porous medium. The temperature field rises with larger values of thermal radiation parameters. Decay in concentration profile is noted when the influence of homogeneous–heterogeneous reactions becomes larger. By increasing the values of the second-grade fluid parameter, the magnetic field parameter and the porous medium, the coefficient of skin friction increases, while it reduces by enhancing the values of the unsteady parameter.
Volume 97, 2023
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