Dual solutions in mixed convection boundary-layer flow with suction or injection

The effect of suction/injection on the laminar mixed convection boundary-layer flow about a vertical wall in an incompressible viscous fluid is considered. The similarity solutions are obtained for some values of the suction/injection parameter as well as the mixed convection parameter for three particular cases: uniform temperature, uniform heat flux and stagnation flow. The resulting system of non-linear ordinary differential equations is solved numerically for both assisting and opposing flow regimes using a finite-difference scheme known as the Keller box method. Numerical results are obtained for the skin friction coefficient and local Nusselt number as well as velocity and temperature profiles. The effects of the involved parameters on the skin friction coefficient and the local Nusselt number characteristics are discussed. It is found that dual solutions exist for assisting flow, besides that usually reported in the literature for opposing flow.