Numerical Investigation and Water Tunnel Experiment for F35 Fighter Jet

In this paper, a low-speed aerodynamic flow structure of the original F35 aircraft model was investigated in a closed-circuit water tunnel experiment, and the investigation was also conducted numerically by using a computational fluid dynamic (CFD) approach. Both studies were performed for the model with a chord length of c =168 mm and wing sweepback angle of Λ = 21.59°, thickness 5 mm and beveled leading edges with an angle of 45°, and for the Reynolds numbers 10.000 at the angle of attack from 5° to 25° with the airflow speed of 0.6 cm/s. For the experimental part, dye visualization and Particle Image Velocimetry (PIV) experiments were performed, and for the numerical part, SST turbulence model was used to solve the flow field around model aircraft and obtained data were compared with experiment. Detail about the flow field including, the development of leading-edge vortex and formation of vortex breakdown and interactions were discussed and presented. Leading-edge vortices were partially developed at the angle of 5°, vortex breakdown pronounced at the angle of 10°, as the increasing angle of attack, location of vortex breakdown moved further up to the front side. At 25°, there was no complete stall condition, and the location of the vortex breakdown stayed on the wing surface.