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

The effect of suction, applied through a porous wall strip of finite stream wise length, on a turbulent boundary layer is investigated using a turbulen ce 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 t he suction strip dimensions are kept the same for all calculations. The ski n friction. mean velocity and Reynolds stress distributions compare well wi th experimental data and DSN data, indicating the appropriateness of the tu rbulence model. For a given suction rate, the effect of suction on the skin friction distribution depends on the Reynolds number, implying that the Re ynolds number should play a nonnegligible role in the relaminarization proc ess 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 la rger Reynolds number, while the recovery of the outer region is less affect ed by the Reynolds number. (C) 2001 Elsevier Science Inc. All rights reserv ed.