Aeroelastic performance of surface jets for load alleviation on flexible aircraft wings

Effective alleviation of aerodynamic peak loads, caused by gusts or maneuvers, allows significant wing‐structure mass reduction and lower energy consumption. Conventional control surfaces, like trailing‐edge flaps, are limited by deflection rates, whereas fluidic actuators, such as wall‐normal surface jets, use pressurized air to achieve a faster response.This study develops and evaluates a surface‐jet design for elastic 3D aircraft wings. First, a 2D RANS‐based parametric study shows that using narrow slots of 0.05\,\% chord width cuts mass flow requirements by 40\,\% at fixed pressure ratios, compared to prior designs, despite lower efficiency at supersonic jet speeds. Chordwise positioning at $x/c = 0.8$ yields greater lift reduction on a stiff 2D wing section, while $x/c = 0.6$ enhances decoupling between lift and pitching moment control, which is beneficial for flexible wings and outboard locations. Two selected actuator geometries are evaluated over varying Reynolds numbers, Mach numbers, and angles of attack to generate a CFD dataset from which a reduced-order model is derived. The model is implemented in a low-fidelity aeroelastic framework, and results show that chordwise placement at $x/c = 0.6$ helps improve aeroelastic effectiveness, achieving ~23\,\% wing-root bending-moment reduction compared to the trim load at $2.16$\,kg/s mass flow, while the most effective spanwise location is determined at 75\,\% span. These results are confirmed by high-fidelity CFD-CSM simulations that also provide further insight into the aeroelastic mechanisms of fluidic load alleviation.