Some Issues and Developments in Analytical and Experimental Work on Turbine Blade Flows

Areas where substantial research on planar turbine cascades is ongoing, or is still needed, are identified. Compressibility effects are particularly important and are addressed in the three main sections. The modeling of the shock-boundary layer interaction is not yet reliable. For supersonic speeds the agreement is excellent apart from the crucial region downstream of the shocks. At subsonic speeds the vortices were shed in a classical von Kármán vortex street. This resulted in strong base pressure deficits causing high wake losses and energy separation in the wake. The base pressure deficit and the measurements of wake energy separation coincide and it is concluded that the two phenomena are both manifestations of von Kármán vortex shedding. At Mach numbers above unity the vortex shedding was found to be one of a number of transient shedding patterns.