On the splitting of G?rtler vortices

摘要

The splitting process of streamwise counter-rotating G?rtler vortices in a concave surface boundary layerflow is demonstrated by pre-setting the vortex wavelength twice of the dominant or most amplifiedwavelength as reported by Mitsudharmadi et al. [1]. The velocity contours in the x-z plane show the splittingof the vortices as indicated by the formation of the low speed streaks between the spacing of the wires. Inthe y-z plane, the splitting of the vortices is shown by the formation of the secondary mushroom-likestructures that are smaller than the primary one. The results also show that spatially developing G?rtlervortices are vulnerable to spanwise disturbances with wavelength twice or 3/2 times that of the dominant one,and the occurrence of the linear instability of the vortices with respect to spanwise perturbation (Eckhausinstability) as have been investigated numerically by Guo and Finlay [2, 3].