  A direct transient growth analysis for three-dimensional perturbations to
flow past a periodic array of T-106/300 low-pressure turbine fan blades is
presented. The methodology is based on a singular value decomposition of the
flow evolution operator, linearised about a steady or periodic base flow. This
analysis yields the optimal growth modes. Previous work on global mode
stability analysis of this flow geometry showed the flow is asymptotically
stable, indicating a non-modal explanation of transition may be more
appropriate. The present work extends previous investigations into the
transient growth around a steady base flow, to higher Reynolds numbers and
periodic base flows. It is found that the notable transient growth of the
optimal modes suggests a plausible route to transition in comparison to modal
growth for this configuration. The spatial extent and localisation of the
optimal modes is examined and possible physical triggering mechanisms are
discussed. It is found that for longer times and longer spanwise wavelengths, a
separation in the shear layer excites the wake mode. For shorter times and
spanwise wavelengths, smaller growth associated with excitation of the near
wake are observed.
