Najwa Najib

Stagnation Point Flow and Mass Transfer with Chemical Reaction past a Stretching/Shrinking Cylinder

This paper is about the stagnation point flow and mass transfer with chemical reaction past a stretching/shrinking cylinder. The governing partial differential equations in cylindrical form are transformed into ordinary differential equations by a similarity transformation. The transformed equations are solved numerically using a shooting method. Results for the skin friction coefficient, Schmidt number, velocity profiles as well as concentration profiles are presented for different values of the governing parameters. Effects of the curvature parameter, stretching/shrinking parameter and Schmidt number on the flow and mass transfer characteristics are examined. The study indicates that dual solutions exist for the shrinking cylinder but for the stretching cylinder, the solution is unique. It is observed that the surface shear stress and the mass transfer rate at the surface increase as the curvature parameter increases.

Stability of dual solutions of mass transfer on a continuous flat plate moving in parallel or reversely to a free stream in the presence of a chemical reaction with second order slip

The present paper investigates the steady viscous flow and mass transfer on a moving plate in parallel or reversely to a free stream in the presence of chemical reaction using a second order slip flow model. The governing partial differential equations are transformed into nonlinear ordinary differential equations by using appropriate similarity transformations, which are then solved numerically using shooting method for different values of selected parameters. We found that dual solutions exist for a certain range of the velocity ratio parameter. By using bvp4c solver in Matlab software, a stability analysis is performed to show that the first solutions are stable and physically relevant, while the second solutions are unstable and not physically relevant. The effects of reaction rate parameter, Schmidt number, first order slip parameter and second order slip parameter on the skin friction coefficient, mass transfer from the surface of the plate, dimensionless velocity and concentration profiles are figu...

Stagnation point flow over a stretching/shrinking cylinder with prescribed surface heat flux

The steady stagnation-point flow towards a horizontal linearly stretching/shrinking cylinder immersed in an incompressible viscous fluid with prescribed surface heat flux is investigated. The governing partial differential equations in cylindrical form are transformed into ordinary differential equations by similarity transformations. The transformed equations are solved numerically by using the shooting method. Results for the skin friction coefficient, local Nusselt number, velocity profiles and temperature profiles are presented for different values of the governing parameters. Effects of the curvature parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are discussed. The study indicate that the solutions for a shrinking cylinder are non-unique. It is observed that the surface shear stress and heat transfer rate at the surface increase as the curvature parameter increases.

Stagnation-point flow and mass transfer with chemical reaction past a permeable stretching/shrinking sheet

An analysis is carried out to investigate the steady two-dimensional boundary layer stagnation point flow past a permeable stretching/shrinking sheet with chemical reaction. Using a similarity transformation, the governing equations are transformed into coupled, nonlinear ordinary differential equations which are then solved numerically using a shooting method. Effects of uniform suction and injection on the flow and mass transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique. The range of parameter b/a where the similarity solution exists for the steady stagnation point flow over a stretching/shrinking sheet with suction effect is larger compared with injection effect. The results indicate that the concentration boundary layer thickness decreases with increasing values of Schmidt number and reaction-rate parameter for both solutions.

Boundary layer flow adjacent to a permeable vertical plate with constant surface temperature

The effects of suction/injection on the laminar boundary layer flow adjacent to a vertical wall with constant surface temperature are considered. The governing partial differential equations are first transformed into ordinary differential equations before being solved numerically by a finite difference method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. It is found that the solution was unique for the assisting flow, while dual solutions exist for the opposing flow. The results indicate that the range of known dual solutions increases with suction and decreases with injection.

Stability of solutions in boundary layer flow and heat transfer over a stretching cylinder

The boundary layer flow and heat transfer in viscous fluid passing through a stretching cylinder with present of mass suction are investigated. The governing equations of boundary layer in the form of partial differential equation are transformed into ordinary differential equations using appropriate similarity variables. The systems of ordinary differential equations are then reduced to first order system before being solved numerically. The results for skin friction coeffiecient, local Nusselt number, velocity and temperature profiles are presented. The effects of mass suction with different values of curvature parameter on the flow and heat transfer characteristics indicate that the dual solutions are found to exist. The stability analysis is performed to verify which solution (first or second solution) is linearly stable and thus the physical meaning is realizable. In the presence of mass suction, the dual solutions exist along stretching cylinder.