RÉSUMÉ

Turbulence control for drag reduction is investigated using direct numerical simulations (DNS) of a turbulent boundary layer. Wall blowing and suction are applied using the opposition control strategy proposed by Choi et al. (1994). The sensitivity and robustness of the wall blowing and suction control are investigated. The effect of the blowing and suction strength is found less important than the phase information. The wall blowing and suction control is robust against moderate random modulation. It is found that the opposition control is very sensitive to the spanwise alignment of the wall blowing and suction. Turbulence characteristics affected by various wall blowing and suction parameters are also discussed.