Aircraft Noise Sources
Imagine Deliverable D9 - Reference and engineering models for Aircraft noise sources
Imagine Deliverable D10
The following WP4 documents are downloadable
Deliverable D9 will be downloadable soon
Description of the Work Package
This work package will provide a harmonised, accepted and reliable method for the assessment of environmental noise levels from airports which links well with the methods for noise propagation description developed in HARMONOISE and, at the same time, have large acceptance in the field of future users and other stakeholders.
This work will involve the the extension of the HARMONOISE Reference and Engineering models to the assessment of Lden and Lnight caused by aircraft noise. For this, it is necessary to develop a method to characterise aircraft noise sources in the same way as the other traffic and industrial sources. This is not trivial for four reasons:
1. whilst the physics of sound propagation is the same in all three dimensions, work in Harmonoise only looked at the horizontal plain and the equations must be adapted to take the vertical plain into account - e.g. temperature and pressure gradients, ground reflection etc.;
2. there are many components in aircraft noise - different parts of the air-frame (flaps, under-carriage etc.), engine fan, engine jet etc. - whose relative importance changes according to which aircraft is considered and with the aircraft's operational configuration and mode of flight;
3. directivity plays a much greater role in aircraft noise source characteristics that in other sources, including its influence over the relative importance of the different source components mentioned above;
4. aircraft noise sources are currently characterised by means of Noise-Power-Distance (NPD) tables in which source characterisation and propagation are mixed;
This work package will, therefore, also provide a supporting method for measuring the sound power and directional characteristics of aircraft noise sources and a conversion method to transform the currently available source (NPD) data into the desired type of representation.
In the spring of 2006 flight tests will be carried out in Spain by WP4 to validate the propagation method developed for aircraft. The Harmonoise propagation method was developed for road and railway noise sources. In Imagine the method is modified for the calculation of sound propagation from the (higher) aircraft noise sources.