Energy transfer mechanisms and resolvent analysis in the cylinder wake

We investigate discrepancies between the two-dimensional cylinder flow and a quasilinear model (i.e.~resolvent analysis) from an energy transfer perspective at Re=100. The energy balances achieved by the true flow are characterized and compared to predictions from resolvent analysis. The impact of the neglected nonlinear energy transfer on the resolvent mode shapes is clarified by analyzing the spatial distribution of the energy transfer mechanisms. This provides insights into the extent to which resolvent analysis correctly models energy transfer mechanisms, which is essential for understanding the limitations of quasilinear approximations and improving the modeling of nonlinear flows.