Unsteady Wake Flow Simulation of Multi-wings in a Schooling Using Viscous Vortex Particle Method

The multi-wings in a schooling can reduce the drag and increase the flight range using the wake in a beneficial way. In order to beneficially use the wake to avoid its adverse effects, the fast and accurate wake simulation method for multi-wings schooling flight is necessary. A numerical method for wake flow simulation and wing load calculation is established based on the viscous vortex particle method (VVPM) and the unsteady panel method (UPM). The numerical method is validated by simulation on the NACA0015 wing, which reveals that the surface load on the wing and the evolution of the wake behind the wing aligned well with the experimental test data. For the multi-wing in a schooling, in order to avoid the phenomenon that the particle will penetrate the downstream wing panel in schooling flight and accurately model the interaction between the wing and wake, the near-wall velocity reconstruction approach for vortex particles is established followed the principle of fluid dynamics. The enhanced approach is used to simulate the wake flow in multi-wings in a schooling and is compared to the high-fidelity CFD method. The results show that VVPM with the velocity reconstruction approach can well model the interaction between the wing and wake, which in turn improves the accuracy of wake simulation.