Numerical investigation on spatial development of the secondary flow in a supersonic turbulent square duct

The development of secondary flow in a supersonic turbulent square duct is numerically investigated in this paper. By comparing with the experimental data, the RSM turbulent model is revealed to be able to predict the secondary flow induced by the anisotropy of turbulence. To identify the corner vortex, the vortex recognition method, Liutex, is employed to extract the vortex structures and their cores. The results show that the spatial development of the corner vortex in the square duct has two stages: the linear growth stage and the stable maintenance stage. Moreover, the propagation of vortex is restricted by the boundary layer and the size of the cross-section. For a square duct, the propagation of the corner vortex in the direction perpendicular to the nearest wall stabilizes first.