Syahira Mansur

The magnetohydrodynamic stagnation point flow of a nanofluid over a stretching/shrinking sheet with suction

The magnetohydrodynamic (MHD) stagnation point flow of a nanofluid over a permeable stretching/shrinking sheet is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of parameters. The numerical results show that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. For the stable solution, the skin friction is higher in the presence of magnetic field and increases when the suction effect is increased. It is also found that increasing the Brownian motion parameter and the thermophoresis parameter reduces the heat transfer rate at the surface.

The Flow and Heat Transfer of a Nanofluid Past a Stretching/Shrinking Sheet with a Convective Boundary Condition

The boundary layer flow of a nanofluid past a stretching/shrinking sheet with a convective boundary condition is studied. Numerical solutions to the governing equations are obtained using a shooting method. The results are found for the local Nusselt number and the local Sherwood number as well as the temperature and concentration profiles for some values of the convective parameter, stretching/shrinking parameter, Brownian motion parameter, and thermophoresis parameter. The results indicate that the local Nusselt number is consistently higher for higher values of the convective parameter. However, the local Nusselt number decreases with increasing values of the Brownian motion parameter as well as the thermophoresis parameter. In addition, the local Sherwood number increases with increasing Brownian motion parameter and decreases with increasing convective parameter and thermophoresis parameter.

The Magnetohydrodynamic Boundary Layer Flow of a Nanofluid past a Stretching/Shrinking Sheet with Slip Boundary Conditions

The magnetohydrodynamic (MHD) boundary layer flow of a nanofluid past a stretching/shrinking sheet with velocity, thermal, and solutal slip boundary conditions is studied. Numerical solutions to the governing equations were obtained using a shooting method. The skin friction coefficient and the local Sherwood number increase as the stretching/shrinking parameter increases. However, the local Nusselt number decreases with increasing the stretching/shrinking parameter. The range of the stretching/shrinking parameter for which the solution exists increases as the velocity slip parameter and the magnetic parameter increase. For the shrinking sheet, the skin friction coefficient increases as the velocity slip parameter and the magnetic parameter increase. For the stretching sheet, it decreases when the velocity slip parameter and the magnetic parameter increase. The local Nusselt number diminishes as the thermal slip parameter increases while the local Sherwood number decreases with increasing the solutal slip parameter. The local Nusselt number is lower for higher values of Lewis number, Brownian motion parameter, and thermophoresis parameter.

Three-dimensional flow and heat transfer of a nanofluid past a permeable stretching sheet with a convective boundary condition

The three-dimensional flow and heat transfer of a nanofluid over a stretching sheet is studied. Numerical solutions are obtained using the boundary value problem solver bvp4c in MATLAB. It is noted that the results obtained for three-dimensional flow are similar to the results obtained in most two-dimensional flow problems. The suction and stretching parameter decrease the skin friction coefficient. On the other hand, increasing the stretching parameter is to increase the local Nusselt number. Although Biot number encourages the heat transfer rate at the surface, increasing thermophoresis parameter and Brownian motion parameter causes the local Nusselt number to decrease.

Three-Dimensional Flow and Heat Transfer Past a Permeable Exponentially Stretching/Shrinking Sheet in a Nanofluid

The three-dimensional flow and heat transfer of a nanofluid over a stretching/shrinking sheet is investigated. Numerical results are obtained using bvp4c in MATLAB. The results show nonunique solutions for the shrinking case. The effects of the stretching/shrinking parameter, suction parameter, Brownian motion parameter, thermophoresis parameter, and Lewis number on the local skin friction coefficient and the local Nusselt number are studied. Suction increases the solution domain. Furthermore, as the sheet is shrunk in the -direction, suction increases the skin friction coefficient in the same direction while decreasing the skin friction coefficient in the -direction. The local Nusselt number is consistently lower for higher values of thermophoresis parameter and Lewis number. On the other hand, the local Nusselt number increases as the Brownian motion parameter increases.

Blasius flow for a copper-water nanofluid with a convective boundary condition

The steady flow over a static plate immersed in a copper-water nanofluid with the bottom surface of the plate heated by convection is considered. Similarity solutions for the flow and the thermal fields are possible if the convective heat transfer from the hot fluid on the lower surface of the plate varies like x−1/2, where x is the distance from the leading edge. The governing partial differential equations are first transformed into a system of ordinary differential equations, before being solved numerically. The results indicate that the inclusion of nanoparticles into the base fluid produces an increase in the skin friction coefficient and the heat transfer rate at the surface.

Boundary layer flow for a nanofluid over a flat plate with a convective boundary condition

The steady flow over a static plate immersed in three different nanofluids (CuO-water, Al2O3-water, TiO2-water) with the bottom surface of the plate is heated by convection is investigated numerically. Similarity solutions for the flow and thermal fields are possible if the convective heat transfer from the hot fluid on the lower surface of the plate varies like x−1/2, where x is the distance from the leading edge. The governing partial differential equations are first transformed into a system of ordinary differential equations, before being solved numerically. The results indicate that the inclusion of nanoparticles into the base fluid produces an increase in the skin friction coefficient and the heat transfer rate at the surface. The rate of heat transfer in the Al2O3-water nanofluid is found to be higher than the rate of heat transfer in the CuO-water and TiO2-water nanofluids.

Stagnation-point flow towards a stretching/shrinking sheet in a nanofluid using Buongiorno's model:

The stagnation point flow of a nanofluid towards a permeable stretching/shrinking sheet using the Buongiornos model is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of the governing parameters. The numerical results show that dual (upper and lower branch) solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the physical realizable in practice of the dual solutions. It is found that the skin friction decreases when the sheet is stretched, but increases when the suction effect is increased. It is also found that increasing the thermophoresis parameter reduces the heat transfer rate at the surface, while increasing the Brownian motion parameter increases the mass transfer rate at the surface.

Unsteady boundary layer flow and heat transfer over a stretching sheet with a convective boundary condition in a nanofluid

The heat transfer characteristics of an unsteady boundary layer flow of a nanofluid past a stretching sheet with a convective surface boundary condition are studied. Numerical solutions to the governing equations are obtained using a shooting method. The results are found for the reduced Nusselt number as well as the temperature profiles for some values of the unsteadiness parameter, convective parameter, thermophoresis parameter, Brownian motion parameter and Lewis number. The results indicate that the reduced Nusselt number is lower for higher values of the unsteadiness parameter, thermophoresis parameter, Brownian motion parameter and Lewis number. However, the reduced Nusselt number increases with increasing values of the convective parameter.

Sensitivity Analysis on Thermal Conductivity Characteristics of a Water-Based Bionanofluid Flow Past a Wedge Surface

Thermobioconvection boundary layer flow in a suspension of water-based bionanofluid holding both nanoparticles and motile microorganisms past a wedge surface was studied. The governing nonlinear partial differential equations on reference of the Buongiorno model were transformed into a set of coupled nonlinear ordinary differential equations. Shooting technique was then used to solve the transformed nonlinear ordinary differential equations numerically. The solutions were found to be contingent on several values of the governing parameters. As highlighted, the velocity profile as well as the skin friction coefficient was affected by the pressure gradient parameter, the function of the wedge angle parameter. On the other hand, the temperature, nanoparticle concentration, and density of motile microorganism’s distributions together with its corresponding local Nusselt number, local Sherwood number, and local density of the motile microorganisms change with the thermophoresis and Brownian motion parameter and so Lewis number, Schmidt number, and bioconvection Peclet number. An experimental scheme together with sensitivity analysis on the basis of Response Surface Methodology (RSM) was applied to examine the dependency of the response parameters of interest to the input parameters’ change. Obviously, local Nusselt number was more sensitive towards the Brownian motion parameter when the Brownian motion parameter was at 0.2 and 0.3. However local Sherwood number was more sensitive towards the Lewis number for all values of Brownian motion parameter. Compatibility found by comparing results between RSM and shooting technique gave confidence for the model’s accuracy. The findings would provide initial guidelines for future device fabrication. Finally, the numerical results obtained were thoroughly inspected and verified with the existing values reported by some researchers.