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