Mixedness in the formation of a vortex ring

The mixing process in the formation of an axisymmetric vortex ring is analyzed by direct numerical simulation. After the initial phase, when the impulse is imparted to the fluid, the mixing increases linearly in time with a slope that is directly proportional to the vortex circulation (Γ) and to reactants diffusivity to the power −1/3 (Pe−0.33). In addition, for reacting flows with equivalence ratio (s) different from 1, it has been found that as s decreases the mixing first decreases and then increases. An explanation for this behavior is given.