Abstract
In turbulent flow, the spanwise spatial correlation around a bluff body is higher than the spanwise correlation of oncoming turbulent flow. Previous studies showed that it was caused by the two dimensional spreading of flow at the transfer from oncoming flow to peel sheering layer. This research tried the modal decomposition to the flow field around a rectangular model including separated bubble with POD and DMD. POD analysis shows the process of two dimensional spreading in the separated bubble. Though this process is not appeared in DMD analysis, the dynamic process of two dimensional spreading in the separated bubble will be revealed by using more appropriate linear mapping.
