Syakila Ahmad

Boundary layer flow over a moving surface in a nanofluid beneath a uniform free stream

Purpose – The purpose of this paper is to theoretically investigate the steady two‐dimensional boundary‐layer flow past a moving semi‐infinite flat plate in a water‐based nanofluid containing three different types of nanoparticles: copper (cuprum) Cu, alumina (aluminium oxide) Al2O3, and titania (titanium dioxide) TiO2. The effects of moving parameter λ as well as solid volume fraction parameter φ on the flow and heat transfer characteristics are studied. Taking into account the rising demands of modern technology, including chemical production, power stations and microelectronics, there is a need to develop new types of fluids that will be more effective in terms of heat exchange performance.Design/methodology/approach – A similarity transformation is used to reduce the governing partial differential equations to a set of nonlinear ordinary differential equations which are then solved numerically using Keller‐box method.Findings – There is a region of unique solutions for λ>0, however, multiple (dual) so...

Unsteady mixed convection boundary-layer flow with suction and temperature slip effects near the stagnation point on a vertical permeable surface embedded in a porous medium

The unsteady mixed convection boundary-layer flow near the two-dimensional stagnation point on a vertical permeable surface embedded in a fluid-saturated porous medium with suction and a temperature slip effect is studied numerically. Similarity equations are obtained through the application of a similarity transformation technique. The shooting method is used to solve these similarity equations for different values of the mixed convection, wall mass suction, the unsteadiness and the slip parameters. Results show that multiple solutions exist for certain ranges of these parameters. Some limiting forms are then discussed, namely strong suction, the free convection limit, the situation when there is a large temperature slip and when the time dependence dominates.

Melting Effect on Mixed Convection Boundary Layer Flow About a Vertical Surface Embedded in a Porous Medium: Opposing Flows Case

The effect of melting phenomenon on the steady mixed convection boundary layer flow about a vertical surface embedded in a fluid-saturated porous medium is numerically studied. The boundary layer partial differential equations are transformed into a set of nonlinear ordinary differential equations by using similarity transformation and then are solved using the shooting method for different values of the mixed convection and melting parameters. Results show that dual solutions exist for a certain range of these parameters. The results also indicate that the melting phenomenon reduces the heat transfer rate and expedites the boundary layer separation.

Mathematical modeling of boundary layer flow over a moving thin needle with variable heat flux

The problem of steady laminar forced convection boundary layer flow of an incompressible viscous fluid over a moving thin needle with variable heat flux is considered. The governing boundary layer equations are first transformed into non-dimensional forms. These equations are then transformed into similarity equations using the similarity variables, which are solved numerically using an implicit finite-difference scheme known as the Keller-box method. The solutions are obtained for a blunt-nosed needle (m = 0). Numerical computations are carried out for various values of the dimensionless parameters of the problem, which include the Prandtl number Pr and the parameter a representing the needle size. It has been found that the wall temperature are significantly influenced by both parameters a and Prandtl number Pr. However, the Prandtl number has no effect on the flow characteristics due to the decoupled boundary layer equations.

Flow over a permeable stretching sheet in micropolar nanofluids with suction

The flow over a permeable stretching sheet in micropolar nanofluids for suction case is investigated. The boundary layer equations are transformed to ordinary differential equations then are solved by using the shooting technique. Copper (Cu), alumina (Al2O3) and titania (TiO2) in water-based micropolar nanofluid have been considered. Results of interest for the skin friction coefficient and the couple stress are obtained numerically for various values of material, nanoparticle volume fraction and mass transfer parameters. The numerical results show that as values of nanoparticle volume fraction parameter increases, the skin friction coefficient and the couple stress decrease. The present values of the skin friction coefficient for viscous fluid are compared with the previous study. The results of velocity and angular velocity profiles are also presented. It is shown that the velocity and angular velocity profiles increase with the decrease of mass transfer parameter or with the increase of material param...

The Mixed Convection Boundary Layer on a Vertical Melting Front in a Non-Darcian Porous Medium

The effect of surface melting on the dual solutions that can arise in the problem of the mixed convection boundary-layer flow past a vertical surface embedded in a non-Darcian porous medium is considered. The problem is described by M, melting parameter,

The Effect of Conducting Sidewalls on the Onset of Convection in a Porous Cavity

\lambda

Unsteady stagnation-point flow and heat transfer past a permeable shrinking sheet in a nanofluid using Buongiorno’s model

λ, mixed convection parameter, and