Experimental Method Measuring Unsteady Force and Moment on Circular Cascading Blades with Splitter Blades. Case of the Cascade Composed of the Same Profile Blades.

An experimental method to measure the unsteady aerodynamic forces and moments acting on the vibrating circular cascading blades which rotate about the main shaft is proposed. Here, we consider that the cascade is composed of two small-scale circular cascades, one of them is harmonically vibrated and the other is interrupted. Unsteady forces and moments acting on a vibrating blade and a standing blade are measured. This manipulation is repeated for the cascades exchanging the motion between two small-scale cascades. Then, the unsteady forces and moments of the cascading blades producing harmonic vibration are obtained by linearly superposing on the measured datum for each amplitude of the blades, hence, the data of interferences between the cascades are obtained. The results obtained using this method were in the good agreement with one by the conventional method and it was applicable to the determination of the unsteady forces and moments on the cascade.