Teaching sequence

Work through this resource material in the following sequence:

10 minutes

Tune In: Wind turbine noise

15 minutes

Find Out: Wave properties

30 minutes

Take Action: Acoustic engineering

5 minutes

Reflection

Learning intentions and success criteria

Students will:

explore the different types of noise generated by wind turbines and investigate how acoustic engineering can mitigate the impact of noise pollution on nearby communities.

Students can:

investigate the types of noise generated by wind turbines and understand their sources and impact
outline the methods used to mitigate noise pollution from wind turbines
evaluate strategies for reducing noise pollution at a wind farm, incorporating technical sound concepts.

Tune In: Wind turbine noise

Step 1

Show your students the images on the first slide of the attached Visual Explainer, or provide students with the following list and ask them to rank the noises from these items from quietest to loudest.

Lawnmower (1m away)
Motorcycle
Normal conversation (1-2m away)
Music Festival
Wind turbine (300m away)
Jet engine (30m away)
Subway train (60m away)
City traffic (inside a car)

Discuss students' responses and justifications for their answers.

The correct order, measured in decibels, is:

Wind turbine from 300m away (50dB)
Normal conversation (60dB)
City traffic (inside a car) (85dB)
Subway train (95dB)
Motorcycle (100dB)
Lawn mower (107dB)
Music Festival (115 dB)
Jet engine (140 dB)

(Sources: Hearing Conservation and Queensland Government Department of Energy and Climate)

Step 2

Ask students to think about the type of noise produced in each example above. Which examples above could be the most impactful if you hear them in an everyday setting, regardless of the decibel measurement?

Read the options out loud and invite students to put up their hands when they hear the example they agree with the most. Discuss responses with students as you go through the options.

Step 3

Encourage students to think not only about the decibel measurement of the sound but also about how often that sound would occur and where it would occur. If you lived near this noise, which would you be apprehensive about?

Invite students to put their hands up again to see if their thinking has changed with this extra thinking time.

Encourage students to consider that noises from things like rock concerts, lawnmowers, jet engines, and motorcycles are often fleeting, even though they are incredibly loud. Since a wind turbine is operating continuously, this type of noise has the potential for greater impact.

Step 4

You might like to share the following video with your students, which shows how a wind turbine operates and talk through the features with your students. Ask your students to brainstorm where the noise would be generated from turbines and wind farms.

How does a wind turbine work? | Sustainability - ACCIONA (youtube.com/watch?v=DILJJwsFl3w)

Find Out: Wave properties

Step 1 (optional)

Depending on the level of prior knowledge of your students, you might like them to refresh and/or consolidate their knowledge of key terms involving waves. You can use the table of key terms on the Student Worksheet for students to fill in the definitions, units (where applicable) and a diagram (where applicable) for each key term involving waves. Activating this prior knowledge will help students understand the following activity's case study and fact sheet.

Step 2

Explain to students that modern wind turbines are designed to be as quiet as possible. Wind turbines and the associated infrastructure of wind farms produce a range of sounds. The noise emissions from wind farms are regulated under various rules and regulations to ensure they have as little negative impact as possible on the environment and people who are located nearby.

Ask your students to brainstorm in their Student Worksheet why it is important to control the noise associated with wind turbines and farms.

Suggested response:

Wind farms are essential for generating clean, renewable electricity. As global energy demand increases and more wind farms are planned and constructed, it is important to ensure that these facilities are as efficient as possible and that they do not negatively impact their surrounding environments and communities.

Step 3

Provide students with the link to this research paper, Wind turbine noise and its mitigation techniques: A review.

Students should read through the start of the paper and answer the following questions.

What information can you find about the impact of wind turbine noise on human populations?
What are the two main types of noise associated with wind turbines?
Explain these types of noise with reference to how the noise is generated and what characteristics this type of noise has.

Suggested responses:

the two main types of noise associated with wind turbines are mechanical and aerodynamic
mechanical noise is generated from various machinery components in the wind turbine. It is predominantly tonal in character, meaning that the noise generated from mechanical sources peaks around certain frequencies and is harsher to human ears than broadband noise.
aerodynamic noise is generated by the flow of air above the blades, which interacts in different ways with the blades' surface. Inflow turbulence noise is caused by the interaction of the blade surface with atmospheric turbulence. This produces sound in the low-frequency spectrum (up to 1000Hz). Airfoil self-noise mechanisms are made up of many different types, including trailing edge noise and tip noise. This noise results from several complex fluid dynamical phenomena that occur on a wind turbine blade and is usually broadband in nature, meaning that the noise signal is spread over a continuous range of frequencies.

Step 4

Explain to students that engineers use science and mathematics to develop practical solutions to complex problems and are among the most in-demand occupations in the renewable energy transformation (Source: Future Energy Jobs Guide). Mechanical engineers such as Mechanical Design Engineers, Manufacturing Engineers and Composite Engineers (among many others) are involved in improving the efficiency of structural components of renewable technologies, such as wind turbines and blades.

Students can find out more about these careers in the Future Energy Jobs Guide.

Invite students to read the following passage in their Student Worksheet from Polytechnique Insights regarding design enhancements for mitigating noise pollution from wind turbines:

“In practice, the challenge facing the designers and operators of wind farms is to reduce the noise generated by the machines to avoid complaints from local residents. Different approaches are being studied or have already been implemented. It is possible to influence the speed of rotation or the angle of pitch of the blades,” explains Benjamin Cotté. “Some teams are working on intelligent tools that automatically regulate wind turbines to minimise noise while optimising production. One of the latest advances is the use of “combs” or “serrations”. These are elongated “saw-toothed” parts directly inspired by the wings of nocturnal birds of prey, which can fly in perfect silence thanks to the spread of their wingtip feathers, which allow air to pass through, thus reducing turbulence.” These combs are attached to the trailing edge of the blades. They reduce aerodynamic noise by an average of 2 to 3 decibels by reducing the turbulence created by air friction at the tip of the blade.

Source: Modelling sound from wind turbines and drones to combat noise pollution - Polytechnique insights

Step 5

Invite students to complete a connect, extend, question thinking routine in their Student Worksheet about what they have read to draw out their thinking and observations about the ways that design can influence this issue. Discuss student responses.

How are the ideas and information in this connected to what you already know?
What new ideas did you get that broadened your thinking or extended it in different directions?
What questions or puzzles emerge for you after reading this?

Take Action: Acoustic engineering

Step 1

Explain to students that acoustic engineers are experts who study and control sound. They work to make places quieter, improve sound quality, and reduce unwanted noise. For example, they design buildings to block out traffic noise, create better sound systems for concerts, and ensure wind turbines are quieter.

Step 2

Allocate students into small groups and task them with writing a report as an acoustic engineer contracted to work on minimising noise pollution for the Coopers Gap Wind Farm, located approximately 250 km northwest of Brisbane. The nearest town of Cooranga has a population of 119, located only a few kilometres away. In their report, they must provide the following information.

How will the Coopers Gap Wind Farm improve Queensland’s renewable energy resources?
Why is it important for noise pollution produced by wind turbines to be minimised?
What design changes can be implemented to reduce noise pollution?
Reference to frequency, decibels and other technical components of sound should be made.

The following resources can be provided to students. However, students should also be encouraged to conduct their own research.

Extension opportunity: Early finishers or students requiring an extension could also consider how wind farm noise can disturb native wildlife. Students could provide some examples of animals that are affected by wind farm noise and include this information in their reports.

Step 3

Bring students back together to share their findings and discuss the design innovations they found for mitigating wind farm noise.

Reflection

Discuss the following points with students to ascertain their level of understanding of the sound waves produced by wind turbines:

What frequency range is generally produced by wind turbines?
What is ‘infrasound’ and why is it harmful?

Designing Wind Turbines for Noise Control

Go to

Summary

Lesson Guides and Printables

In this lesson

Designing Wind Turbines for Noise Control

Go to

Summary

Lesson Guides and Printables

In this lesson