Interaction noise mechanisms for an advanced propeller - Experimental results

The interaction mechanisms associated with wakes incident upon rotating propfan blades are presently studied experimentally in order to generate a database for the improvement of noise-prediction methodology components and achieve a deeper understanding of interaction-noise generation. A single, stationary, swept fan blade representative of a state-of-the-art profan was used to generate a wake upstream of a single-rotating propfan and gather interaction noise measurements. A potentially dominant interaction noise-source mechanism, related to a velocity defect associated with the leading edge vortex of the swept blade, was identified. This vortex defect/blade interaction generated significant blade surface pressure fluctuations.