Calculation of the effect of concentrated wall suction on a turbulent boundary layer using a second-order moment closure

Abstract

The effect of suction, applied through a porous wall strip of finite streamwise length, on a turbulent boundary layer is investigated using a turbulence model, based on a second-order moment closure. Calculations are carried out at two Reynolds numbers and two suction rates. To allow for a pertinent comparison between the Reynolds numbers the boundary layer thickness and the suction strip dimensions are kept the same for all calculations. The skin friction, mean velocity and Reynolds stress distributions compare well with experimental data and DSN data, indicating the appropriateness of the turbulence model. For a given suction rate, the effect of suction on the skin friction distribution depends on the Reynolds number, implying that the Reynolds number should play a non-negligible role in the relaminarization process when wall suction is applied. The suction seems to disturb the flow in a roughly similar manner at both Reynolds numbers, but the severity of the disturbance is reduced at the higher Reynolds number. The near-wall region of the boundary layer recovers over a shorter streamwise distance at the larger Reynolds number, while the recovery of the outer region is less affected by the Reynolds number.