AIRCRAFT FUSELAGE NOISE TRANSMISSION MEASUREMENTS USING A RECIPROCITY TECHNIQUE

The cabin noise environment in typical turbo-prop aircraft is high. To evaluate potential noise reduction approaches, a method of predicting the internal noise is desired that avoids costly flight tests. Instead of carrying out a ground simulation of the propeller sound pressure field, a much simpler reciprocal technique can be used if a computed pressure field is available. A capacitive scanner is used to measure the fuselage vibration response on a deHavilland Dash-8 fuselage, due to the internal noise source. The approach is validated by comparing this reciprocal noise transmission measurement with the direct measurement. The fuselage noise transmission information is then combined with computer predictions on the propeller sound pressure field data to predict the internal noise at two points.