Asymptotic accelerated boundary layer over the permeable wall

•Analytical solution for asymptotic boundary layer is obtained.•Asymptotic skin-friction function determines influence of acceleration or suction.•At certain conditions suction and acceleration have to be considered in combination.•Combined influence of acceleration and suction extends the asymptotic flow region.

The paper reports on numerical and analytical investigation of the laminar boundary layer with a favorable pressure gradient over a permeable wall. Researchers have obtained an analytical solution of boundary layer equations for asymptotic flow conditions. This solution allows proposing a relative asymptotic skin-friction function, which determines a degree of influence of flow acceleration and permeable wall on the flow. There are ranges of this function, where effects of permeable wall and streamwise pressure gradient have to be considered only in combination. Numerical simulation has showed that such combined influence of favorable pressure gradient and permeable wall extends the asymptotic flow. The study of a strong gas blowing into the accelerated flow has revealed that favorable pressure gradient impedes separation of the boundary layer. At that asymptotic flow starts from the point, where the separation would occur at gas injection into the zero-pressure gradient flow.