Note on the effect of boundary-layer suction on separation

Abstract

It is well known that the separation point of a boundary-layer flowing over an impermeable surface is defined by the vanishing of the skin friction at that point. Previous investigations have assumed that this condition applies equally to the flow over a porous surface through which the boundary layer is being withdrawn by suction. This appears, however, not to be strictly accurate, and the object of this note is to examine the significance of the distinction and to suggest by means of physical arguments the general character of the flow near a separation point.