Improving Aircraft Noise Predictions Considering Fan Rotational Speed

摘要

Accurate predictions of aircraft noise levels are desirable to enforce noise control regulations around airports and to evaluate noise abatement procedures. The current best practice noise contour prediction models assume certain default net thrust values depending on the engine type and aircraft altitude. This Paper proposes a method for calculating the engine fan settings N1% (and, hence, the net thrust) directly from audio recordings. This method was tested with a large number of Airbus A330-300 and Boeing 777-200 flyover audio recordings. A significant correlation was found between the recorded noise levels and N1%, explaining up to 45% of the variability in the noise levels. Using the calculated N1% values in the noise prediction models, instead of the default values, increases the agreement with the actual recorded noise levels and explains parts of the variability. The inclusion of accurate values of N1% and the update of the aircraft noise prediction calculations is therefore highly encouraged, for example, by increasing the dependency on N1% of the noise levels.