The recent development of the lattice Boltzmann method enables its widespread application in various industrial areas. However, in the simulation of complicated industrial problems, considerable grid numbers are required to achieve reasonable resolution in the near-wall region due to the lack of a local refinement method on the geometry. This study proposes a new hybrid grid refinement method, which comprises the reconstruction algorithm in refined near-wall nodes on the refinement interface and the in-domain interpolation multi-grid method to prevent the local distortion of the pseudo-wall among resolution levels. The proposed method is validated on a two-dimensional flat plate and NACA0012 airfoil at low and high Reynolds numbers. Furthermore, the aerodynamic and aeroacoustics of a pair of counter-rotating propellers are simulated with the proposed lattice Boltzmann method and compared with the results obtained using commercial software.

The flow control effect of the trailing-edge Gurney flap (TG) on the dynamic lift characteristics for a 50°-swept delta wing during large-amplitude pitching oscillations at various reduced frequencies (k = 0.072, 0.144, 0.287, and 0.575) was investigated via force, particle image velocity, and dye visualization measurements in a water channel facility. Numerical simulations were carried out to further understand the flow control mechanism of the TG in low and high reduced frequency cases (k = 0.072 and 0.575). It was found that as the reduced frequency increases, the lift increments brought by the TG are magnified and abated during the upstroke and downstroke processes, respectively. The breakdown of the leading-edge vortex (LEV) on the upper surface of the wing is promoted by the TG during the early stage of the pitching cycle. The lift enhancement being benefited by the TG is mainly contributed by the recovery of lower surface pressure along the trailing edge due to the blockage effect of TG, which also stimulates the spanwise flow and strengthens the LEV upon the upper surface. The significant lift increment contribution of the upper surface during the upstroke process can be maintained to higher angle of attack as the reduced frequency increases.