xi engineering technical brief noise...xi engineering technical brief tonal noise produced by wind...

Xi Engineering Technical Brief

Tonal noise produced by wind turbines is a serious

communities. Tonal noise emissions are subject to strong regulatory pena

complete closure of wind turbines. Xi Engineering Consultants have been solving tonal noise issues in wind turbines for over seven

years for clients throughout the United Kingdom, Europe, North America and Asia

Noise from wind turbines has two main sources;

train. Mechanical noise is produced by the

generator. These systems produce discrete vibrations at specific fre

vibrations interact with a large radiating surface

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E Xi’s established process begins with a detailed vibration and acoustic survey of the tone emitting turbine by our working at

height accredited engineers. This typically takes

23m or 200m. Xi’s survey process is accurate and

with the problematic noise, which can then be linked through

pathway, and radiating surface to be established

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Following measurements, Xi establish the precise

structural-acoustic modelling techniques

from the vibration and acoustic survey.

access to supercomputing facilities for the largest and most complex of systems.

virtual test-bed to determine the best solution for the turbine and optimise the solution.

ST

AG

E 3

SO

LUT

ION

An optimal solution for one wind turbine may not be the most effective for another. Xi’s well established 3 stage process

provides the fundamental knowledge for specifying an effective and efficient solution

refined and tested in a virtual environment,

noise mitigation has seen us develop a range of tonal noise mitigation techniques, from increasing the damping of the

turbine tower to stopping frequency matching between co

frequencies below 800 Hz, especially at the traditionally challenging low frequencies, providing significant tonal

reductions, of between 8 and 15 dB.

1 MEASURE

Call Xi’s Engineering Team to discuss in confidence how to maximise

your turbine’s acoustic performance

Up to 15 dBHow Xi Mitigates Tonal Noise from Wind Turbines

Xi Engineering Technical Brief

T +44 (0)131 290 2250 E enquiries@xiengineering.com

Tonal noise produced by wind turbines is a serious and often complex issue which can be particularly annoying to

subject to strong regulatory penalties resulting in; curtailment

Xi Engineering Consultants have been solving tonal noise issues in wind turbines for over seven

throughout the United Kingdom, Europe, North America and Asia.

Noise from wind turbines has two main sources; aerodynamic noise, and mechanical noise associated with components in the drive

the rotating machinery within the nacelle of the turbine such as th

produce discrete vibrations at specific frequencies. Problematic or excessive noise occurs when these

radiating surface such as the blades or tower walls - much like the cone of a loudspeaker system.

Xi’s established process begins with a detailed vibration and acoustic survey of the tone emitting turbine by our working at

This typically takes 1 to 3 days depending on the scale of the turbine; be it a tip height of

23m or 200m. Xi’s survey process is accurate and safe. The measurements characterise the precise frequencies associated

which can then be linked through all the measurement points

to be established.

Xi establish the precise dynamics of the tonal noise by simulating the system using

ling techniques. The model is constructed using engineering drawing

from the vibration and acoustic survey. The model analysis utilises Xi’s extensive internal computational resource with

omputing facilities for the largest and most complex of systems. Once validated, the model

bed to determine the best solution for the turbine and optimise the solution.

turbine may not be the most effective for another. Xi’s well established 3 stage process

provides the fundamental knowledge for specifying an effective and efficient solution. This solution is then

refined and tested in a virtual environment, allowing a full cost benefit analysis for all options. Xi’s success in developing

noise mitigation has seen us develop a range of tonal noise mitigation techniques, from increasing the damping of the

turbine tower to stopping frequency matching between components. Our solutions have proved extremely effective at

frequencies below 800 Hz, especially at the traditionally challenging low frequencies, providing significant tonal

reductions, of between 8 and 15 dB.

2 MODEL 3 SOLUTION

Call Xi’s Engineering Team to discuss in confidence how to maximise

your turbine’s acoustic performance

15 dB Reduction in Tonal NoiseHow Xi Mitigates Tonal Noise from Wind Turbines

Xi Engineering Technical Brief

Xi Engineering Consultants

enquiries@xiengineering.com xiengineering.com

particularly annoying to residential

tailment, loss of yield and even the

Xi Engineering Consultants have been solving tonal noise issues in wind turbines for over seven

mechanical noise associated with components in the drive

of the turbine such as the gearbox or the

Problematic or excessive noise occurs when these

much like the cone of a loudspeaker system.

Xi’s established process begins with a detailed vibration and acoustic survey of the tone emitting turbine by our working at

1 to 3 days depending on the scale of the turbine; be it a tip height of

. The measurements characterise the precise frequencies associated

all the measurement points allowing the vibration source,

by simulating the system using our in-house

using engineering drawings and validated using data

The model analysis utilises Xi’s extensive internal computational resource with

Once validated, the model then acts as a

turbine may not be the most effective for another. Xi’s well established 3 stage process

. This solution is then optimised,

allowing a full cost benefit analysis for all options. Xi’s success in developing

noise mitigation has seen us develop a range of tonal noise mitigation techniques, from increasing the damping of the

mponents. Our solutions have proved extremely effective at

frequencies below 800 Hz, especially at the traditionally challenging low frequencies, providing significant tonal

SOLUTION

Call Xi’s Engineering Team to discuss in confidence how to maximise

oise How Xi Mitigates Tonal Noise from Wind Turbines