The effects of distributed suction on the development of turbulent boundary layers

Abstract

Summary. Experiments have been performed on the turbulent boundary layer with uniform suction and with zero pressure gradient. The test surface consisted of a uniformly perforated sheet which replaced the floor of a wind tunnel, the tunnel boundary layer being removed through a slot a short distance ahead of the test section. For several different suction velocities, and for different entry conditions, boundary-layer measurements were made on the perforated surface and on a porous surface formed by covering the perforated sheet with calendered nylon fabric. For certain conditions it was found that both the thickness and the velocity profile of the turbulent boundary layer remained constant over virtually the full length of the suction surface, thus establishing the existence of a turbulent asymptotic layer. At sufficiently high rates of suction it was found that an initially turbulent layer reverted to the laminar asymptotic form.