Study on topology and vortex structure in a diffusion cascade

To further make clear vortex structures in diffusion cascades so as to help understand the mechanisms of vortex affecting loss production, the emergence, evolution and development of secondary flow vortexes, including horse shoe vortex, passage vortex and corner vortex and so on, were discussed mainly through using the topological analysis method and numerical calculation. The concept of a three-dimensional dividing surface between the low energy flow zone and the exterior flow zone was presented. The results show that concentrated shed vortex is located outside the dividing surface (in the outer flow zone) and horse shoe vortex, passage vortex and corner vortex are inside the dividing surface (in the low energy flow zone). Dissipation function is used to measure loss production instead of using entropy production. The results about loss analysis indicate that vortex motion directly causes loss production, namely, peak value of loss is generally located around the core of vortex and that maximal loss happens around the dividing surface other than in the low energy flow zone.