Microjets arranged on the wing surfaces of civil transport aircraft have been shown to have great potential in suppressing high-frequency gust loads. This paper presents a study of aerodynamic load reduction on a supercritical airfoil using tilted microjets by solving the Reynolds-averaged Navier-Stokes (RANS) equations. The numerical method was first validated against the experimental and previous numerical data. Afterward, the subsonic and transonic flowfields around the supercritical airfoil were simulated with various angled microjets. The results show that both the lift reduction and the power efficiencies significantly increase as the blowing direction shifts downstream to upstream. The movement and weakening of the shock due to the jet are observed at α > 2 ∘ in transonic flow, resulting in a drag reduction compared to the baseline airfoil. However, the transient subsonic results revealed that the upstream jet induces a strong vortex shedding, which is suppressed in transonic flows. During jet deployment, there are three distinct phases: time lag, vortex rolling-up, and rebalancing, in that order. Once it reaches the trailing edge in subsonic flows, the starting vortex rapidly modifies the load and induced a strong roll-up vortex from the pressure surface. Nevertheless, in transonic flow, the rebalancing stage contributes to a greater reduction in lift due to the additional shock movement and weakening effect.

This paper presents a numerical investigation on the lift augmentation at subsonic speeds by using lateral jets for a hypersonic aircraft equipped with a waverider-type lifting body, which consists of three main parts. The jet slots were arranged along the side edges of the lifting body to study the effect of lateral blowing on the lift augmentation at a freestream Mach number of 0.3. The numerical results based on solving the Reynolds-averaged Navier–Stokes equation indicate that a well-designed lateral blowing can produce a significant lift rise. Then, further work was carried out to investigate the effects of jet parameters, including the jet location, the blowing strength and the blowing direction on lift augmentation, and to provide insights into the associated flow physics. It was found that blowing on the middle and rear parts of the lifting body achieves the maximum lift augmentation among the chosen configurations. Additionally, it was confirmed that the lift augmentation increases as the jet momentum increases, and blowing in the direction of θjet = −45°, which means the jet blows slightly towards the lower surface of the lifting body, produces a larger lift rise than other directions. The lift augmentation can be explained by the fact that a well-designed lateral blowing can amplify the effectiveness of the vortices shedding from the side edges of the lifting body, resulting in an increase in the vortex lift.