New approaches to modelling vortex rings and vortex ring-like structures

The paper presents an overview of recent progress in the modelling of vortex rings and vortex ring-like structures with specific potential applications to direct injection gasoline engines. A new theoretical model for a confined axisymmetric vortex ring is described. The predictions of this model are shown to be in agreement with available experimental data and numerical simulations. Direct numerical simulations (DNS) are used to test the range of applicability of the model and to investigate new physical features of confined vortex rings recently reported in the experimental studies. A meshless method for modelling of 2D transient, non-isothermal, two-phase flows with phase transitions, based on a combination of the viscous-vortex and thermal-blob methods for the carrier phase with the Lagrangian approach for the dispersed phase, is briefly described. The flow parameters were found from the solution of three systems of ordinary differential equations, describing the motion of viscous-vortex blobs, thermal blobs and droplets. Potential applications of the results to modelling the processes in direct injection gasoline engines are discussed.