Vortex ring impacting on wall

Three dimensional vortex ring impacting a wall at different angles of incidence has been numerically investigated using the lattice Boltzmann model. The detailed flow behavior, vortex evolution, and pressure distribution on wall have been studied systematically with the Reynolds number of 100 $<$ Re $<$ 1000, and the impact angle of the range of 0\r{ } $< \quad \theta \quad <$ 60\r{ }. Our results show that only when Re $>$ 100, the interaction of the vortex ring with the wall can generates the secondary vortex rings. The evolution of vortex structure is also strongly influenced by $\theta $. The increase of $\theta $ will cause a wrap process of the secondary vortex ring and an obvious suppression of the tertiary vortex ring generation. Further more, the study identified new features of vortex structure and its interaction with wall, in particular, for the oblique impact scenarios. A simple model is adopted to describe the basic characteristics of pressure distribution on the wall along the symmetry vortex ring plane at low Reynolds number.