Vortex Ring Collision with Free-Slip and No-Slip Wall

Vortex ring collision on wall explains azimuthal instability, stretching, vorticity and wall turbulence in a simplified way, required in many applications. Present study performs high Reynolds number (2500 and 4000) simulations of vortex rings approaching no-slip and free-slip walls for different radius ratio (0.1, 0.2, 0.3, and 0.4). Structural and dynamic information, statistics on energy transfer and vortex stretching obtained using the simulations. Three-dimensional simulations helped to understand the mechanism of the formation of azimuthal instabilities and their dependence on Reynolds number and radius ratio, and verified that these instabilities influence the ejection velocity of the new ring, and the generation of small-scale turbulence. Interaction between a ring and a wall compared from that of a vortex pair collision. Axisymmetric simulations performed to help to verify whether the generation of small scales of the new vortex ring is due to azimuthal instabilities or other phenomena.