*Kriebel, Anthony R (Massachusetts Institute of Technology) Seidel, Barry S (Massachusetts Institute of Technology) Schwind, Richard G*

*naca-tn-4134*

*Jul 1958*

(Massachusetts Institute of Technology) An experimental investigation of stall propagation in a stationary circular cascade in which high-speed schlieren and interferometer photography is used is described. This investigation suggests an analytical approach to the study of stall propagation which is valid only for an isolated blade row in an infinite flow field but which is not restricted to small unsteady perturbations or to an assumed simplified cascade geometry. Conditions necessary for the existence of the assumed type of stall cells are described and equations are derived for the velocity of stall-cell propagation. The propagation velocities predicted for the theoretical potential-flow model correlate with all the experimental values measured in an isolated rotor within 15 percent. Analysis of the flow model leads to the prediction of a tendency for the assumed type of stall cell to split with increasing incidence of the mean flow through the blade row. This tendency appears to correspond with the experimental observation of a trend for increasing numbers of cells in the rotor.

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