Viscous fluid flow and heat transfer past a permeable wall jet with convective boundary conditions

Purpose The steady laminar wall jet flow over a stretching/shrinking surface in the presence of lateral suction or injection with a convective boundary condition is considered. Design/methodology/approach The partial differential equations for mass, momentum and energy conservation are changed to the system of ordinary differential equations through similarity solution transformations. Solutions, both numerical and asymptotic, to these similarity equations are found in some new ranges of parameters in the governing equations. Findings The equations are solved both asymptotically and numerically for a range of the transpiration parameter S and the flow parameter lambda given in Mahros et al. (2023), thus greatly extending the range of these previous solutions. Asymptotic solutions for both large and small values of the Prandtl number sigma are derived, showing good agreement with additional numerical integrations. It should be noted that in Mahros et al. (2023), only the case when sigma=1 was treated. A solution for large lambda when S=1 is obtained, showing a different asymptotic form to the case when S>0 in Mahros et al. (2023). Multiple solutions were seen by them for S<0 and the nature of the lower solution branch as S -> 0 from below is discussed. The question as to whether the lower branch solutions join as lambda>0 when S<0 is resolved through obtaining an asymptotic solution lambda small. Originality/value The accuracy of the solutions has been checked through a detailed comparison between the solutions obtained numerically and analytically, where excellent agreement has been found. This study is important for scientists working in the area of jet flows to become familiar with the flow properties and behaviour of jets.