PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Low-level jets create winds of change for turbines

Strong, energetic flows in the lower atmosphere can greatly enhance wind farm performance, if the height is right.

Low-level jets create winds of change for turbines
2021-02-23
(Press-News.org) WASHINGTON, February 23, 2021 -- As one of the leading sources of clean and renewable energy, global wind power capacity has increased more than fivefold over the past decade, leading to larger turbines and pushing wind technology to its limits.

"These much larger turbines are operating in very different atmospheric layers than smaller turbines used 5-10 years ago," said Srinidhi Gadde, one of the authors of a paper in the Journal of Renewable and Sustainable Energy, from AIP Publishing, that examines the impacts of turbine height. "At these scales, local meteorology and extreme shear events, which frequently occur, can impact power production."

Low-level jets, which are maxima in wind velocity in the lower atmosphere, are one cause for concern with growing turbines. These strong, energetic wind flows can either have desirable or detrimental effects on the turbines, depending on how high the wind flows are in relation to the turbines.

"A simple way to think about LLJs is to visualize them as high-velocity 'rivers' or 'streams' of wind within the atmosphere," Gadde said.

In their simulation of a wind farm with a 4-by-10 grid of turbines, Gadde and co-author Richard Stevens considered three different scenarios in which the LLJs were above, below, and in the middle of the turbine rotors.

When the jets and the turbines were at the same height, the researchers found the front rows blocked wind access downstream, causing a reduction in power production in each successive row. Relative to this equal height scenario, a larger downstream energy capture was observed in both other cases, though by different mechanisms.

For high jets, the turbulence generated in the wakes of the turbines pulls the wind from the upper atmosphere down toward the turbines in a process called downward vertical kinetic energy entrainment, leading to large amounts of power production. More surprisingly, when the jets are low, the reverse process occurs. High-velocity wind from the LLJ is pushed upward into the turbine, a previously unknown phenomenon, which the authors termed upward vertical kinetic energy entrainment.

Gadde said he looks forward to applying this work to drive innovation and functionality to meet future power demands, which will require an even deeper understanding of events like LLJs and additional observations of these phenomena.

"As one of the leading renewable energy technologies, wind energy is expected to deliver major contributions to the expected growth in renewable energy production in the coming decades," he said.

INFORMATION:

The article "Effect of low-level jet height on wind farm performance" is authored by Srinidhi N. Gadde and Richard J.A.M. Stevens. The article will appear in Journal of Renewable and Sustainable Energy on Feb. 23, 2021 (DOI: 10.1063/5.0026232). After that date, it can be accessed at https://aip.scitation.org/doi/full/10.1063/5.0026232.

ABOUT THE JOURNAL

Journal of Renewable and Sustainable Energy is an interdisciplinary journal that publishes across all areas of renewable and sustainable energy relevant to the physical science and engineering communities. Topics covered include solar, wind, biofuels and more, as well as renewable energy integration, energy meteorology and climatology, and renewable resourcing and forecasting. See https://aip.scitation.org/journal/rse.


[Attachments] See images for this press release:
Low-level jets create winds of change for turbines

ELSE PRESS RELEASES FROM THIS DATE:

Parasitic plants conspire to keep hosts alive

Parasitic plants conspire to keep hosts alive
2021-02-23
The plant that encourages kissing at Christmas is in fact a parasite, and new research reveals mistletoe has an unusual feeding strategy. Like other plants, mistletoe is capable of using sunlight to create its own food, a process called photosynthesis. However, it prefers to siphon water and nutrients from other trees and shrubs, using "false roots" to invade its hosts. "Plants are autotrophic, they make their own food. Humans are heterotrophic, we eat it," explained UC Riverside plant-insect ecologist Paul Nabity. "Mistletoe are mostly heterotrophic, but they can switch if they want to." Nabity's team found when two mistletoes invade the same tree, they increase photosynthesis to get the nutrients they need, essentially sharing the ...

Kittens could hold key to understanding deadly diarrheal disease in children

2021-02-23
Kittens could be the model for understanding infectious, sometimes deadly, diarrheal disease in both animals and children, according to new research from North Carolina State University. Diarrheagenic Escherichia coli (DEC) bacteria cause lethal diarrheal disease in children worldwide, killing up to 120,000 children under the age of five annually. Atypical enteropathic Escherichia coli (aEPEC) are a form of DEC increasingly associated with diarrheal disease in humans and in kittens. "We were looking for causes of infectious diarrhea in kittens, which has a high mortality rate, and came across this pathogen," says Jody Gookin, FluoroScience Distinguished Professor in Veterinary Scholars Research Education at NC State and corresponding ...

Genetic tool improves estimation of prostate cancer risk in diverse ethnic/racial groups

2021-02-23
Building upon previous research, an international team led by scientists at University of California San Diego School of Medicine, has validated a more inclusive and comprehensive genetic tool for predicting age of onset of aggressive prostate cancer, a disease that killed more than 33,000 American men in 2020. Reporting in the February 23, 2021 online edition of Nature Communications, the researchers describe the performance of a polygenic hazard score (PHS) -- a mathematical estimate of an individuals' age-specific genetic risk for developing a disease -- in a multi-ethnic patient population. "Genetic tools to predict a man's lifetime risk of prostate cancer might allow us to target cancer screening efforts to the men who are most likely to need it. We are ...

University of Minnesota researchers develop two new rapid COVID-19 diagnostic tests

2021-02-23
MINNEAPOLIS/ST.PAUL (02/23/2021) -- University of Minnesota Medical School researchers have developed two new rapid diagnostic tests for COVID-19 - one to detect COVID-19 variants and one to help differentiate with other illnesses that have COVID-19-like symptoms. The findings were recently published in the journal Bioengineering. Although many people are hopeful about COVID-19 vaccines, widespread vaccine distribution isn't predicted to be available until several months from now. Until that happens, the ability to diagnose COVID-19 quickly and accurately is crucial to help minimize loss of life and ...

Protective ship coatings as an underestimated source of microplastic pollution

2021-02-23
Shipping traffic can be a major source of tiny plastic particles floating in the sea, especially out in the open ocean. In a paper published in the scientific journal Environmental Science & Technology, a team of German environmental geochemists based at the University of Oldenburg's Institute of Chemistry and Biology of the Marine Environment and led by Dr Barbara Scholz-Boettcher for the first time provides an overview of microplastics mass distribution in the North Sea. The scientists found that most of the plastic particles in water samples taken from the German Bight, an area in the south-eastern corner of the North Sea which encompasses some of the world's busiest shipping lanes, originate from binders used in marine paints. "Our hypothesis is that ships leave ...

New blood pressure-lowering guidelines could benefit 25 million americans with chronic kidney disease

2021-02-23
A recommendation for more intensive blood pressure management from an influential global nonprofit that publishes clinical practice guidelines in kidney disease could, if followed, benefit nearly 25 million Americans, according to an analysis led by researchers at the Johns Hopkins Bloomberg School of Public Health. The new recommendation from Kidney Disease: Improving Global Outcomes, a global nonprofit that develops evidence-based clinical practice guidelines in kidney disease, is aimed at doctors to help them to reduce blood pressure for chronic kidney disease patients whose systolic blood pressure levels are over 120 mmHg. Blood pressure can be reduced using antihypertensive medications and lifestyle modifications. ...

Multi-ethnic neighborhoods in England retain diversity unlike in the U.S.

2021-02-23
Multi-ethnic neighborhoods in England retain their diversity and are much more stable than such neighborhoods in the U.S., according to geographers from the U.S. and U.K. The team examined how neighborhood diversity has changed on a national scale from 1991 to 2011 using U.K. Census data. Past studies of this kind have often focused on neighborhoods in which the presence of two or three different ethnic groups constituted a diverse neighborhood but this study applied a more rigorous standard. A multi-ethnic neighborhood had to have at least five or more ethnic groups represented and no group could represent more ...

'Good bacteria' in breast milk changes over time

Good bacteria in breast milk changes over time
2021-02-23
The cocktail of beneficial bacteria passed from mother to infant through breast milk changes significantly over time and could act like a daily booster shot for infant immunity and metabolism. The research, conducted by scientists from Montreal and Guatemala and published in Frontiers in Microbiology, has important implications for infant development and health. Researchers discovered a range of microbiome species never before identified in human milk. Until now, relatively little was known about the role microbiome bacteria play in breast milk. These bacteria are thought to protect the infant gastrointestinal tract and improve aspects of long-term health, such as allergy ...

Toxins from one bacterial species contribute to genetic diversity of others

2021-02-23
A toxin produced by bacteria as a defence mechanism causes mutations in target bacteria that could help them survive, according to a study published today in eLife. The finding suggests that competitive encounters between bacterial cells could have profound consequences on the evolution of bacterial populations. When bacterial cells come into contact, they often produce toxins as a defence mechanism. Although it is known that the bacteria producing these toxins have a competitive advantage, exactly how the toxins affect the recipient cells is less clear. "Undergoing intoxication is not always detrimental for cells - there are scenarios in which encountering a toxin could provide a benefit, such as generating antibiotic ...

Biopolymer-coated nanocatalyst can help realize a hydrogen fuel-driven future

Biopolymer-coated nanocatalyst can help realize a hydrogen fuel-driven future
2021-02-23
To combat climate change, shifting from fossil fuels to clean and sustainable energy sources is imperative. A popular candidate in this regard is hydrogen, an eco-friendly fuel that produces only water when used. However, the efficient methods of hydrogen production are usually not eco-friendly. The eco-friendly alternative of splitting water with sunlight to produce hydrogen is inefficient and suffers from low stability of the photocatalyst (material that facilitates chemical reactions by absorbing light). How does one address the issue of developing a stable and efficient photocatalyst? In a study recently published in Applied Catalysis B: Environmental, ...

LAST 30 PRESS RELEASES:

Pink skies

Monkeys are world’s best yodellers - new research

Key differences between visual- and memory-led Alzheimer’s discovered

% weight loss targets in obesity management – is this the wrong objective?

An app can change how you see yourself at work

NYC speed cameras take six months to change driver behavior, effects vary by neighborhood, new study reveals

New research shows that propaganda is on the rise in China

Even the richest Americans face shorter lifespans than their European counterparts, study finds

Novel genes linked to rare childhood diarrhea

New computer model reveals how Bronze Age Scandinavians could have crossed the sea

Novel point-of-care technology delivers accurate HIV results in minutes

Researchers reveal key brain differences to explain why Ritalin helps improve focus in some more than others

Study finds nearly five-fold increase in hospitalizations for common cause of stroke

Study reveals how alcohol abuse damages cognition

Medicinal cannabis is linked to long-term benefits in health-related quality of life

Microplastics detected in cat placentas and fetuses during early pregnancy

Ancient amphibians as big as alligators died in mass mortality event in Triassic Wyoming

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Study links teen girls’ screen time to sleep disruptions and depression

Scientists unveil starfish-inspired wearable tech for heart monitoring

Footprints reveal prehistoric Scottish lagoons were stomping grounds for giant Jurassic dinosaurs

AI effectively predicts dementia risk in American Indian/Alaska Native elders

First guideline on newborn screening for cystic fibrosis calls for changes in practice to improve outcomes

Existing international law can help secure peace and security in outer space, study shows

Pinning down the process of West Nile virus transmission

UTA-backed research tackles health challenges across ages

In pancreatic cancer, a race against time

Targeting FGFR2 may prevent or delay some KRAS-mutated pancreatic cancers

[Press-News.org] Low-level jets create winds of change for turbines
Strong, energetic flows in the lower atmosphere can greatly enhance wind farm performance, if the height is right.