Separation control and lift enhancement of a conformal-slot co-flow-jet wing

To mitigate the aerodynamic penalty of conventional co-flow-jet (CFJ) wings when the jet is off due to slot discontinuity, a conformal-slot CFJ wing (S809-based) was designed and evaluated in a wind tunnel using static force measurements and particle image velocimetry. With the jet off, the conformal-slot CFJ wing achieves near-baseline performance, with only a 1.82% average decrease in lift coefficient and a 0.25% average increase in drag coefficient. With the jet on, aerodynamic performance improves markedly as the jet momentum coefficient Cμ increases: the maximum lift coefficient rises by 40.01%, the maximum lift-to-drag ratio by 132.59%, and stall is delayed from 16° to 18°. Time-averaged velocity fields show a reduced separation region and a downstream shift of the separation point; at α = 16° and Cμ = 0.1, the low-speed separated region vanishes and the flow remains attached. Mean and phase-resolved vorticity indicate that continuous momentum injection accelerates shear-layer transition and suppresses separation–vortex growth, leading to a shift from separation-dominated to attachment-dominated flow.