Interferometric study of unsteady passing shock flow in a turbine cascade

To further advance the state of the art in axial turbomachinery, a better understanding of unsteady phenomena within transonic turbines (including potential flow interaction, wake passing, and shock-wave passing) is required, Recently, the transonic turbine cascade facility at Virginia Polytechnic Institute and State University was modified to allow the study of unsteady passing shock flow. The steady interferometric system in place was updated to allow for a time-resolved, quantitative study of the density field produced by a single shock passing event. Variations in both the cascade inflow and flow through the transonic blade passages were quantized during the shock passage. The full density field in the cascade is presented at six discrete time intervals. A significant rise in the flow density, both upstream and on the suction side of the blade passage, was noted.