Global linear stability analysis of time-averaged flows

The global linear stability analysis (LSA) of stationary/steady flows has been applied to various flows ill the past and is fairly well understood. The LSA of time-averaged flows is explored in this paper. It is shown that the LSA of time-averaged flows call result in useful information regarding its stability. The method is applied to Study flow past a cylinder at Reynolds number (Re) beyond the onset of vortex shedding. Compared with the direct numerical simulation, LSA of the Re = 100 steady flow severely Underpredicts the vortex shedding frequency. However, the LSA of the time-averaged flow results in the correct value of the non-dimensional frequency, St, of the associated instability. Copyright P 2007 John Wiley & Sons, Ltd.