The flow mechanism leading to the enhanced performance of a discrete co-flow jet (dCFJ) airfoil is investigated. Flow visualization and DPIV are used to analyze the difference between the flow along discrete jets and over the tabs used for discretization of the slot jet. Results show that the entrainment is uniform over the leading jet as long as the tab size is small enough. The jets expand spanwise, inducing downward momentum toward the surface of the airfoil. Combined with the momentum increase due to the CFJ, the dCFJ is shown to dramatically increase lift up to 150% from the baseline airfoil and delay separation up to 10 o angle of attack. More results and analysis will be presented in the final paper.