Applied Acoustics at TNO · PDF filethe underwater acoustic ‘signature’ of naval...

Management and control of noise and vibration remains a key issue

for health, safety and well-being of society as a whole. Noise exposure

and annoyance have to be kept within limits both in the environment, at

the workplace, on the move and in the home. With increasing numbers

of sound sources around us, the technology and solutions to better

design and control them are essential. Acoustical techniques are also

used for diagnostic purposes and detection. In the field of acoustics

TNO offers expertise and innovative solutions covering environmental

noise, occupational noise, product quality, detection and diagnostics

technology. TNO can develop intregral solutions by taking the whole chain

from source to receiver into account, in a multidisciplinary approach.

Applied Acoustics at TNO

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Environmental noise sources and propagation

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TNO has been active in acoustics for several decades, providing R&D

and consultancy services for industry and the public sector on noise

control at the source, in the propagation path and on exposure and

perception at the receiver. Capabilities include model development

(numerical and theoretical), experimental testing and monitoring,

system and software development, product innovation and impact

and policy studies. Through involvement in European research,

standardisation work and links with universities and partners, a

broad range of expertise and solutions is available.

Environmental noise assessment, modelling and control

Railway noise expertise at TNO includes modelling and measurement

of rolling noise of vehicle/track systems including steel bridges, curve

squeal, traction, braking and aerodynamic noise and other sources.

Prototypes of low noise track and bridges have been developed,

now put into practice. TNO has developed several measurement

procedures for noise emission at railway yards and for type testing.

A special test rig for research on curve squeal has been built. The

TNO Pass-by Analysis (PBA) software allows measurement of vehicle

and track characteristics including combined roughness and track

decay rates from a single train pass-by. Both trackside and on-board

monitoring measurements are performed, either for type testing or

analysis purposes.

Road traffic and vehicle noise

Environmental noise is a key expertise at TNO, including noise at

the source, propagation and perception, for road, railway, aviation,

shipping, industrial and military noise. TNO is closely involved in

the development of the Dutch statutory calculation schemes and

new European prediction models such as Harmonoise/IMAGINE.

Prediction models for both noise and air quality are combined in

URBIS and the interactive 3D planning tool Urban Strategy. Model-

based monitoring tools are available for the assessment of noise-

sensitive locations such as motorways in cities, junctions, railway

yards and airports. Advanced propagation models developed at TNO

such as PE, which also can be coupled to meteorological models, are

used to predict sound propagation over large distances. These models

allow modelling of geometrically complex situations including

street canyons, propagation over built-up areas and over water and

undulating landscapes. Detailed studies have been performed on

noise barrier design and on meteorological effects such as reswing

(affecting transmission over barriers).

Road traffic is a major noise source. Using model-based monitoring

techniques and noise mapping, TNO can evaluate vehicle noise

emissions on motorways and in urban areas. This provides insight

into current trends and vehicle and infrastructural noise control

measures such as traffic management, barrier design and vehicle

Noise map of Rotterdam in Urban Strategy

requirements. The TRIAS model for road/tyre noise has been

developed enabling prediction of noise emission of different tyre

designs. In the scope of the Qcity project a decision support system

is being developed that allows the assessment of action plans as

required for the European Environmental Noise Directive. TNO has

also played a role in the Dutch PIEK programme on the assessment

and reduction of goods delivery noise.

Vehicle noise monitoring on a motorway

Calculation of noise transmission on a road noise barrier T-top

Railway noise

Noise testing on a freight train with low noise brakes

Curve squeal test rig


Assessment and control of industrial noise at TNO includes site

noise mapping, source location, troubleshooting, investigation and

configuration of noise control measures. This is done for example for

harbour facilities, process industry, manufacturing plants, logistics

facilities and others. Abatement measures include operational

control, layout, component selection, acoustic devices such as

silencers, enclosures, vibration isolation, damping and absorption. A

special example is a study in the Rotterdam harbour area where the

sound propagation is studied over land-water crossings to receivers

in a town several kilometers away.

Noise around airports is an ongoing issue with continuing growth

in air traffic. TNO has performed source strength measurements at

airports and proposed new solutions such as novel architecture and

ground profiling along runways to reduce aircraft ground noise.

Active noise control solutions are under development for reducing

noise received in dwellings. Model-based monitoring around airports

has been developed to allow prediction of the dynamic noise map

of individual aircraft depending on the type, the position, power

settings, angle of ascent and weather conditions.

Aircraft noise

Source modelling of aircraft and predicted impact

Measurement of aircraft ground noise

Ship acoustics, underwater acoustics and sonar

For five decades TNO has provided R&D and consultancy services

to navies and commercial shipbuilding industries. A wide range of

analytical, experimental and computational knowledge and tools are

available, and solutions include both passive and innovative active

technologies to isolate noise sources. Due to the high demands on

the underwater acoustic ‘signature’ of naval ships, the low noise

philosophy is present early in the design stage, as well as the search

for cost-effective solutions. The knowledge obtained in this field is

also applied to control the impact of man-made underwater noise on

the environment.

Netherlands Navy Frigate

Industrial noise

Dry bulk terminal at Rotterdam

Underwater technology research at TNO, both theoretical and

experimental, covers underwater observation systems, underwater

environment and underwater threats. Core competences are:

design, construction and testing of passive and/or active sonar

systems for application in anti-submarine warfare, mine counter

measures and torpedo defense; supplying of innovative underwater

technology systems; consultancy partner of the Royal Netherlands

Navy in their role as smart specifier, purchaser and user of

underwater technology.


Impulsive noise such as firearms and explosives is a particularly

critical source, as it causes stronger reactions and is perceived

differently from continuous sources such as traffic noise. To enable

the prevention or reduction of unwanted effects of these sounds,

TNO has designed many field and laboratory studies on audibility,

loudness, annoyance, startle and sleep disturbance. The experimental

results have led to an efficient general method for rating. Control

measures for impulsive sources have been developed. Source and

propagation models developed at TNO have resulted in a decision

support tool that allows scheduling of military exercises, depending

on the noise propagation over large distances affected by weather

conditions.

Impulsive and military noise

Firearms noise emission measurement

Ground-borne vibration

Ground-borne vibration from roads, railways and construction

work are a source of structural damage, vibration annoyance and

vibration induced low frequency noise in buildings. TNO performs

measurements and calculations to assess and predict the effects of

vibration and designs innovative mitigation measures at the source,

in the ground and in buildings. From global assessments to detailed

modelling, much attention is paid to uncertainty and reliability.

Vibration measurements in a new railway tunnel

Noise emission of machinery, appliances and vehicles often needs to

be limited due to environmental, occupational, detectibility, product

quality or comfort requirements.

TNO has the tools and expertise to diagnose and analyse the noise

sources and transmission paths, and the knowledge of noise control

solutions suitable for practical application. For the development

of quieter products, measurement diagnostics are applied besides

calculation tools including FEM, BEM, SEA, CAA, CFD and some

developed in house such as EQUIP+, CABIN and Exhaust. Application

examples are construction and materials handling machinery, medical

equipment, vehicle interior noise, office and household applicances,

plant equipment and production machines. Standard testing can be

performed in both laboratory and field conditions. Flow acoustics

facilities and models are available.

Product improvement and noise control at source

Diagnostic noise measurements on the hydraulic unit of a firefighting vehicle

EQUIP+ Noise path model of a compressor


Besides environmental noise monitoring, asset and machinery

condition monitoring systems can be designed and tested either as

permanent or temporary remote installations. The Andante system

developed for monitoring environmental noise at railway yards, can

locate and characterise the noise source and register it on video.

Monitoring of noise using microphone arrays is used to detect and

locate incidents in public spaces.

After many years of research, active noise and vibration control is

finding more practical applications due to faster algorithms, less

expensive, lighter and more powerful hardware. TNO develops ANVC

systems for specific applications including passenger compartments,

enclosures, panels, isolators and machinery components. Several

patents have been granted and modular control software and

hardware are available.

Active noise and vibration control

Reduction of sound transmission using piezo panels

Noise and vibration monitoring

Ultrasonic measurement technology

TNO is specialised in ultrasonic inspection techniques for

fluids, materials and structures. Applications include flow rate

measurement, particle detection, corrosion monitoring of piping and

inspection of welding joints. A software tool has been developed

which allows the prediction of wave propagation in structural

Simulation of ultrasonic testing of piping joints (UMASIS software)

Architectural acoustics

To improve the acoustic climate in buildings TNO has well established

models for sound transmission in buildings for airborne sources such

as service equipment and for impact sources such as footstep noise.

For the proper modelling of existing buildings and new designs,

focus is on measurement and calculation of the acoustic properties of

building elements and systems, helping industry to innovate.

Sound insulation measurements on a window in an insulation chamber

Perception and dose-effect relationships

Perception of different types of noise source and subsequent

annoyance can differ per source type and are often related to

psychological factors. For example shooting noise, high speed trains

and road traffic may be perceived quite differently depending on the

association made by the observer, but also on the context, situation

and combination with other sources and non-acoustical factors (light,

odour, vibration). TNO performs both field surveys and laboratory

studies to investigate sound perception, taking into account

psychological, subjective and sound quality aspects. Community

surveys have been used to derive dose-effect relationships for

components and joints (UMASIS). This is used to prototype

measurement systems and diagnose measurement results.

Andante monitoring system for noise events at railway yards


TNO Science and IndustryMichael Dittrich, Frank van den BergAcoustics DepartmentStieltjesweg 1, 2628 CK Delft, The NetherlandsT +31 15 269 24 01 / 24 20F +31 15 269 21 [email protected]@tno.nl

TNO Built Environment and GeosciencesJeroen BorstVan Mourik Broekmanweg 6, P.O. Box 49, 2600 AA Delft, The NetherlandsT +31 15 269 47 35F +31 15 269 68 [email protected]

TNO Defence, Security and SafetyTon van Koersel Oude Waalsdorperweg 63, P.O Box 968642509 JG The Hague, The NetherlandsT +31 70 374 03 57F +31 70 374 06 [email protected]

Joos VosBusiness Unit Human FactorsKampweg 5, 3769 DE Soesterberg, The NetherlandsT +31 34 635 62 23F +31 34 635 39 [email protected]

[email protected]

Acoustics

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the effect of transportation on self-reported annoyance and sleep

disturbance. The percentage of (highly) annoyed or sleep-disturbed

people can be predicted for a given exposure level and source. Also

physiological parameters indicating sleep disturbance have been

investigated, such as movements and autonomic nervous system

activity during sleep, as well as effects on health parameters such as

hypertension and cardiovascular disease.

Measurements in a room with variable acoustics

Speech and hearing

TNO applies scientific knowledge about human auditory and

speech production systems to enhance human performance in

a technical environment. The main research topics are Hearing

(including binaural/spatial hearing, 3D audio, hearing protection,

noise annoyance, design and evaluation of warning signals),

Speech Communication (including intelligibility, quality, speaker

recognizability, certification of public address systems, overall

assessment in real-time scenarios) and Speech Technology (speaker

identification and verification, keyword spotting, evaluation of

speech-to-speech translation and text-to-speech systems).

Research on spatial perception of sound

TNO’s clients include:National, municipal and European authoritiesMinistry of Defence and defense organisationsInfrastucture design and management organisationsRailway companies and industryNavies and commercial shipbuilding industriesAutomotive industry and associationsAircraft industry and airportsProcess industries and suppliersManufacturers of machinery, equipment and appliancesSupply industries for building and constructionEngineering companies

FacilitiesAnechoic chambersReverberation and transmission chambersNumerical tools for vibro-acoustic analysisMultichannel measurement equipmentMonitoring systemsWind tunnelScale model

TNO software packages


Applied Acoustics at TNO · PDF filethe underwater acoustic ‘signature’ of naval...

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