Infrasound from a 60-turbine wind farm was found to propagate to distances up to 90 km under nighttime atmospheric conditions. Four infrasound sensor arrays were deployed in central New Mexico in February 2014; three of these arrays captured infrasound from a large wind farm. The arrays were in a linear configuration oriented southeast with 13, 54, 90, and 126 km radial distance and azimuths of 166°, 119°, 113°, and 111° from the 60 1.6-MW turbine Red Mesa Wind Farm (RMWF), Laguna Pueblo, New Mexico, USA.

Peaks at a fundamental frequency slightly below 0.9 Hz and its harmonics characterize the spectrum of the detected infrasound. The generation of this signal is linked to the interaction of the blades, flow gradients, and the supporting tower. The production of wind-farm sound, its propagation, and detection at long distances can be related to the characteristics of the atmospheric boundary layer. First, under stable conditions, mostly occurring at night, winds are highly stratified, which enhances the production of thickness sound (TS) and the modulation of other higher-frequency wind turbine sounds. Second, nocturnal atmospheric conditions can create low-altitude waveguides (with altitudes on the order of 100s of meters) allowing long distance propagation. Third, night and early morning hours are characterized by reduced background atmospheric noise that enhances signal detectability. This work describes the characteristics of the infrasound from a quasi-continuous source with the potential for long-range propagation that could be used to monitor the lower part of the atmospheric boundary layer.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2014JD022821

On infrasound generated by wind farms and its propagation in low‐altitude tropospheric waveguides

Outdoor to indoor reduction of wind farm noise for rural residences

In most jurisdictions containing wind farms, base noise limits have been set by local regulatory authorities, with the intention of protecting the amenity of surrounding communities. It is a standard requirement that during the planning process for a new wind farm, the developer demonstrates that the proposed wind farm will comply with the relevant limits. At present, results from noise prediction models are commonly presented without uncertainty values, despite the fact that simplifications and approximations have been made in the models. Therefore, when prediction models indicate that the wind farm will generate noise within 3 dB of base noise limits, it is likely that these limits will be exceeded. Despite the fact that regulatory authorities often require that compliance measurements are taken to validate predictions of wind farm noise, it is very difficult to make substantial changes to noise emissions, without a corresponding reduction in electrical power output. Current methods of compliance assessment do not provide an indication of the amount of time that wind farms exceed allowable noise limits as they focus on ‘average’ levels only. Therefore, it is possible for wind farms to exceed allowable limits on a regular basis, and by significant margins. Hence, a more conservative approach is warranted during wind farm noise prediction and it is proposed that the upper level of the uncertainty estimate of the prediction model should not be permitted to exceed the allowable level.

Wind Farm Noise Uncertainty: Prediction, Measurement and Compliance Assessment

This study explores the development of thin panels that can be controlled electronically so as to provide surfaces with desired reflection coefficients Such panels can be used as either perfect reflectors or absorbers They can also be designed to be transmission blockers that block the propagation of sound The development of the control system is based on the use of wave separation algorithms that separate incident sound from reflected sound In order to obtain a desired reflection coefficient, the reflected sound is controlled to appropriate levels The incident sound is used as an acoustic reference for feedforward control and has the important property of being isolated from the action of the control system speaker In order to use a panel as a transmission blocker, the acoustic pressure behind the panel is driven to zero Detailed experimental results are presented showing the efficacy of the algorithms in achieving real-time control of reflection or transmission The panels are able to effectively

Active control of sound reflection, absorption and transmission using thin panels

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Zhu

Author Tools

Chat about Author

Papers

Active control of sound reflection, absorption and transmission using thin panels