Some unsteady effects on flows over blading

Accurate turbomachinery design requires the effects of unsteadiness to be taken into account. A distinction is made between unsteadiness intrinsically or latently present in nominally steady flows over blading and unsteadiness externally imposed on these. Examples are drawn from experimental results on turbulent spots, vortex shedding from turbine blades having a blunt trailing edge, and the interaction effects of the wakes of upstream blade rows. Special attention is given to the impact on blading response of the various resulting boundary layer regimes.