Application of a copper vapour laser to investigation of shock and blade interaction in a shock tube

A shock tube is used to simulate the behavior of an aeroengine compressor stator vane during surge. Stator vanes are tested both singly and in a cascade to observe their dynamic behavior under loading from a backward traveling shockwave. Conventional instrumentation is augmented by two optical techniques. Shadowgraph flow visualization allows the shock front transition through the cascade to be visualized, while optical grid projection allows the dynamic reaction of the vane to be measured. For both optical techniques a novel light source is employed. A copper vapor laser is used, providing an intense train of short optical pulses capable of freezing these fast-moving phenomena. The experimental optical equipment is described and the results of the optical measurements are presented and briefly discussed.