The investigation of lateral/heading characteristics and the influence of jet control at high attack angle

Abstract

When the aircraft does high maneuvers at a high attack angle, the rapid transition of flight state induces a series of complex flow phenomena such as flow separation and vortex breakdown, leading to a series of uncommanded motions such as self-excited roll oscillation, which brings great danger to the flight of the aircraft. Therefore, it is important to investigate the mechanism of this phenomenon and suppress it. In this paper, the numerical method is based on Lattice Boltzmann Method (LBM) and Large Eddy Simulation (LES) for the SACCON standard flying-wing layout aircraft model. The accuracy of the numerical method is validated by comparing the simulation results of aerodynamic loads at different attack angles with the experimental results. Then the phenomena of the vortex breakdown and shedding at different roll angles and sideslip angles at high attack angles are analyzed, and the relationship between the jet flow coefficient and the control moment is obtained by adding the jet flow to the fuselage. Finally, the rolling motion of the aircraft is simulated in the dynamic simulation. The simulation results show that the model generates self-excited roll oscillations around a nonzero mean angle at high attack angles. The dynamic numerical simulation based on the LBM method can be an effective complementary tool for the study of the dynamic characteristics of the aircraft with a high attack angle.