The largest ever European aircraft
noise research project, known as SILENCE(R), was launched On April 1st
2001. A consortium of 51 companies will collaborate for four years to
validate new technologies for reducing aircraft noise by up to 6 decibels
as of 2008. The European Commission's Fifth Framework Programme for RTD
is funding 50% of the project whose total budget exceeds 110 M Euro.
No other effect of air transport operations is felt
as directly as aircraft noise. Aircraft landings and take-offs at airports
generate repeated high peaks of noise that occur quickly and then fade
away. While the number of people annoyed by aircraft noise is determined
by a variety of factors, including the number of aircraft movements and
population patterns around airports, a key area of improvement remains
reduction of noise at the source, that is the development of quieter aircraft.
to the test
together a wide-ranging consortium to address the issue of aircraft
noise, a major cause of concern around European airports. First,
partners will carry out a large-scale validation programme, focusing
on noise reduction technologies whose development was initiated
by EU and National projects in 1998. Then, an assessment will be
made of the applicability of these technologies within the European
aeronautics industry, including their effects on cost, weight and
performance. Finally, the associated achievable noise reduction
will be evaluated.
Novel concepts to be validated are to
include low-noise fans, LP turbines, scarfed intakes, novel intake
liners, bypass and hot-stream liners, nozzle jet noise suppressors,
active control techniques and airframe noise reduction technologies.
|| A top-flight
of the SILENCE(R) project is a clear sign of the European aeronautics
industry's commitment to a quieter environment," says project
co-ordinator Eugene Kors. "Increasing air traffic means more
jobs and a stronger economy for Europe, and this project will help
us to minimise the environmental downside."
"All of the major European air engine and
airframe manufacturers are involved in the project," says Kors,
"as well as the major research institutes and a number of universities.
We have also been successful in including SMEs from around Europe.
It was quite a task getting everyone together on this," he
adds. "We now have companies working together which would normally
be fierce commercial competitors."
SILENCE(R) is linked to X-Noise,
a European Thematic Network on external aircraft noise and builds
upon the results of other projects carried out under the Fourth
and Fifth Framework Programmes, including: DUCAT,
investigating computational methods for the propagation and radiation
of turbofan noise; JEAN,
concerned with the prediction of jet exhaust noise; RAIN,
reducing airframe and installation noise; RANNTAC,
developing low-noise turbofan engine nacelles; RESOUND,
reducing noise within the engine itself; SOURDINE,
proposing noise-reducing measures around airports; TURBONOISECFD,
using Computational Fluid Dynamics (CFD) software to predict engine
noise during the design phase. Together, these complementary projects
represent a well-rounded programme aimed at reducing aircraft noise.
||Living up to new
standards for noise reduction
The air transport
industry, over its history, has already achieved major reductions
in the noise made by typical commercial jet aircraft. An aircraft
entering the fleet today is typically 20dB quieter than a comparable
aircraft of 30 years ago. In practice this corresponds to a reduction
in noise annoyance of around 75%, with modern turbojets generating
only 1% of the acoustic energy generated by the first commercial
designs. Current research programmes are expected to deliver the
technology for a further 10dB reduction within the next decade.
A reduction of 10dB is perceived by the human ear as a halving of
the noise experienced.
On 17 January 2001 in Montreal, the Committee
on Aviation Environmental Protection (CAEP) of the International
Civil Aviation Organization (ICAO) developed a comprehensive series
of recommendations to reduce the environmental impact of aircraft
noise. CAEP endorsed a balanced approach to noise mitigation, consisting
of four distinct and complementary elements, including reduction
of noise at source, and a new noise standard which is 10dB lower,
on a cumulative basis, than the current standards.
Seen in this context, the SILENCE(R) project
would seem to be an appropriately bold response, going a long way
towards answering the call for the quieter aircraft of the future.
The project's kick-off meeting took place in Copenhagen last April
and was capped by a public session involving presentations by the
European Commission and major industrial partners on the objectives
and technical content of the project.
For information: Contact the X-Noise/SILENCE(R)
communication manager Dominique Collin at email@example.com
aircraft manufacturers and operators throughout the world facing
increasing pressure to reduce the environmental impact of air
traffic, the reduction of aircraft noise has become a priority
for the New
perspectives in aeronautics key action.
- Significantly lower community exposure to aircraft noise.
Other related projects:
DUCAT - Basic research on duct acoustics and
JEAN - Jet exhaust aerodynamics and noise;
RAIN - Reduction of airframe and installation
RANNTAC - Reduction of aircraft noise by nacelle
treatment and active control;
RESOUND - Reduction of engine source noise through
understanding and novel design;
SOURDINE - Study of optimisation procedures
for decreasing the impact of noise;
TURBONOISECFD - Turbomachinery noise source
CFD models for low noise aircraft engine designs.