Sonic crystal noise barriers
Lead Research Organisation:
University of Salford
Department Name: Res Inst for the Built and Human Env
Abstract
Outdoor noise barriers are used to reduce noise disturbance from fixed industrial plant, from aircraft ground operations and from roads. Recent years have seen a growing interest in the potential for use of sonic crystals as noise barriers. Sonic crystals take their name from the analogous effects of photonic crystals on light. They consist of periodic arrays of circular cylinders and are known to give high attenuation at selective frequencies as a consequence of multiple scattering. The frequencies of highest attenuation can be found by assuming that an integer number of half wavelengths fits the distance between the scatterers. One of the main advantages of sonic crystals (SCs) is that by varying the distance between the cylinders it is possible to attain peaks of attenuation in a certain range of frequencies. One advantage of an SC barrier would be its relative optical transparency. Another would be its relative permeability to wind, thus reducing the effects of barrier induced turbulence and wind-gradient enhancement. In principle, if SC barriers are used as highway noise barriers on both sides of a road, there should be less reverberation than between solid barriers. The appearance of an SC barrier might also have a rather positive aesthetic impact. After all, the interest in using SCs as barriers started with the discovery that a 'sculpture' consisting of vertical parallel cylinders acted as a sound barrier. Various possible designs of SC barriwers will be considered. In addition to 'conventional' vertical circular cylinder arrays, the acoustical performance of horizontal cylinders arrays above a reflecting plane, ellipsoidal cylinder arrays and curved arrays will be investigated both analytically/numerically and through laboratory measurements. The optimisation of the design of SC arrays making use of acoustic lens effects and coverings will be investigated. The acoustical performance of vertical cylinder arrays in configurations suitable for road traffic noise will be tested and compared with that of a simple barrier in various wind conditions by the Transport Research Laboratory.
People |
ORCID iD |
Olga Umnova (Principal Investigator) |
Publications
Krynkin A
(2011)
Scattering by coupled resonating elements in air
in Journal of Physics D: Applied Physics
Romero-García V
(2013)
Multi-resonant scatterers in sonic crystals: Locally multi-resonant acoustic metamaterial
in Journal of Sound and Vibration
Umnova O
(2013)
Comparisons of two effective medium approaches for predicting sound scattering by periodic arrays of elastic shells.
in The Journal of the Acoustical Society of America
Taherzadeh S
(2012)
Aperiodicity effects on sound transmission through arrays of identical cylinders perpendicular to the ground.
in The Journal of the Acoustical Society of America
Krynkin A
(2010)
Predictions and measurements of sound transmission through a periodic array of elastic shells in air.
in The Journal of the Acoustical Society of America
Krynkin A
(2013)
Analytical approximations for low frequency band gaps in periodic arrays of elastic shells.
in The Journal of the Acoustical Society of America
Krynkin A
(2011)
Acoustic insertion loss due to two dimensional periodic arrays of circular cylinders parallel to a nearby surface
in The Journal of the Acoustical Society of America
Krynkin A
(2011)
Scattering by coupled resonating elements in air
Anton Krynkin
(2011)
An effective medium model for sonic crystals with composite resonant elements
Description | Recent years have seen a growing interest in the potential for use of sonic crystals as noise barriers. Sonic crystals take their name from the analogous effects of photonic crystals on light. They consist of periodic arrays of circular cylinders and are known to give high attenuation at selective frequencies as a consequence of multiple scattering. The frequencies of highest attenuation can be found by assuming that an integer number of half wavelengths fits the distance between the scatterers. Additional attenuation bands may be achieved if the array is composed of resonant elements instead of solid cylinders. Possibly the main advantage of sonic crystals (SCs) is that by varying the distance between the cylinders and the design of the resonant elements it is possible to attain peaks of attenuation in a certain range of frequencies. Another advantage of an SC barrier would be its relative optical transparency. Another would be its relative permeability to wind, thus reducing the effects of barrier induced turbulence and wind-gradient enhancement. In principle, if SC barriers are used as highway noise barriers on both sides of a road, there should be less reverberation than between solid barriers. The appearance of an SC barrier might also have a rather positive aesthetic impact. After all, the interest in using SCs as barriers started with the discovery that a 'sculpture' consisting of vertical parallel cylinders acted as a sound barrier. Various possible designs of SC barriers have been considered. In addition to 'conventional' vertical circular cylinder arrays, the acoustical performance of horizontal cylinders arrays above a reflecting plane as well as arrays of elastic shells and composite resonant elements was investigated both analytically/numerically and through laboratory measurements. The optimisation of the design of SC arrays making use of acoustic lens effects and resonances was investigated. The outdoor performance of vertical cylinder arrays of resonant elements in configurations suitable for road traffic noise have been tested and compared with that of a simple barrier in various wind conditions. |
Exploitation Route | Sonic crystal noise barriers can be used to reduce noise disturbance from fixed industrial plant, from aircraft ground operations and from roads. In academic sector, the models and experimental techniques developed during the work on the project can be generalised to the arrays of different resonant scatterers. Currently, the use of coupled scatterers to achieve very low frequency bandgaps is being investigated by several research team worldwide. |
Sectors | Aerospace, Defence and Marine,Communities and Social Services/Policy,Construction,Environment,Transport |
Description | The primary use has been in securing a further EPSRC grant EP/K037234/1 which is being used to pursue some of the results particularly concerning use of coupled resonant elements. The work on sonic crystal barriers was used also in collaboration with a small company Liminal which helped them to win the PRSF new music award in 2010 resulting in a touring sonic crystal demonstrator 'The Organ of Corti'. Several final year projects for BEng and MSc acoustics degrees at Salford University have been based on the ideas emerged during the duration of the project. The results have been used also to inform research carried out for DSTL, UK. |
First Year Of Impact | 2012 |
Sector | Aerospace, Defence and Marine,Education |
Impact Types | Cultural |
Description | Membrane metamaterials |
Amount | £30,000 (GBP) |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Sector | Public |
Country | United Kingdom |
Start | 01/2012 |
End | 07/2012 |
Description | Omnidirectional blast absorber |
Amount | £30,000 (GBP) |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Sector | Public |
Country | United Kingdom |
Start | 11/2011 |
End | 07/2012 |
Description | Senior Visiting Researcher |
Amount | € 15,000 (EUR) |
Organisation | Pays de la Loire Region |
Sector | Public |
Country | France |
Start | 05/2012 |
End | 09/2013 |
Description | DSTL |
Organisation | Defence Science & Technology Laboratory (DSTL) |
Country | United Kingdom |
Sector | Public |
PI Contribution | The models and the devices/ structures developed during the project |
Collaborator Contribution | Testing facilities, advice on the use of the project outcomes for military applications |
Impact | The collaboration is still in its early stage so there are no any particular outcomes yet |
Start Year | 2014 |
Description | University of Burgundy, France |
Organisation | University of Burgundy |
Country | France |
Sector | Academic/University |
PI Contribution | An analytical model has been developed by O.U. for a joint paper published in Journal of the Acoustical Society of America in October 2015 |
Collaborator Contribution | A numerical model and experiments for this paper have been performed by research team in ISAT, University of Burgundy, France |
Impact | A joint paper has been submitted to Journal of the Acoustical Society of America A joint PhD project with ISAT has started in October 2016 |
Start Year | 2014 |
Description | collaboration with LAUM, University of Maine, France |
Organisation | University of Maine |
Country | United States |
Sector | Academic/University |
PI Contribution | Analytical models edeveloped by O.U. have been published in two joint papers. O.U. lead a submission of COST proposal in 2013 (unsuccessful), which was prepared in collaboration with research team from LAUM. |
Collaborator Contribution | Numerical models. COST proposal has been prepared jointly. |
Impact | Two joint research papers published in 2013. COST grant proposal in 2014 (unsuccessful). |
Start Year | 2012 |