Turbulent drag reduction by means of alternating suction and blowing jets

The performance of an alternating suction/blowing jet (ASBJ) actuator array is tested in a water channel for Reynolds numbers ranging from Rex=3.8×105 to 5.7×105. The control method is used to show that local wall shear stress variations give a drag reducing effect of up to 10% at X′=50mm (X′+≃1000) downstream from the ASBJ actuator array for the non-dimensional timescale of suction/blowing frequency Tp+=430 and Rex=5.7×105. The Reynolds stress measured by a PIV system is also reduced at the same location.