Featured Research

from universities, journals, and other organizations

Better turbine spacing for large wind farms

Date:
February 7, 2011
Source:
Johns Hopkins University
Summary:
Large wind farms are being built around the world as a cleaner way to generate electricity, but operators are still searching for the most efficient way to arrange the massive turbines that turn moving air into power. For maximum efficiency in power generation, operators of large wind farms should space their turbines farther apart, researchers say.

In wind tunnel experiments at Johns Hopkins, air currents pass through a series of small model wind turbines mounted atop posts, mimicking an array of full-size wind turbines.
Credit: Will Kirk/JHU

Large wind farms are being built around the world as a cleaner way to generate electricity, but operators are still searching for the most efficient way to arrange the massive turbines that turn moving air into power.

To help steer wind farm owners in the right direction, Charles Meneveau, a Johns Hopkins fluid mechanics and turbulence expert, working with a colleague in Belgium, has devised a new formula through which the optimal spacing for a large array of turbines can be obtained.

"I believe our results are quite robust," said Meneveau, who is the Louis Sardella Professor of Mechanical Engineering in the university's Whiting School of Engineering. "They indicate that large wind farm operators are going to have to space their turbines farther apart."

The newest wind farms, which can be located on land or offshore, typically use turbines with rotor diameters of about 300 feet. Currently, turbines on these large wind farms are spaced about seven rotor diameters apart. The new spacing model developed by Meneveau and Johan Meyers, an assistant professor at Katholieke Universiteit Leuven in Belgium, suggests that placing the wind turbines 15 rotor diameters apart -- more than twice as far apart as in the current layouts -- results in more cost-efficient power generation.

Meneveau presented the study results recently at a meeting of the American Physical Society Division of Fluid Dynamics. Meyers, co-author of the study, was unable to attend.

The research is important because large wind farms -- consisting of hundreds or even thousands of turbines -- are planned or already operating in the western United States, Europe and China. "The early experience is that they are producing less power than expected," Meneveau said. "Some of these projects are underperforming."

Earlier computational models for large wind farm layouts were based on simply adding up what happens in the wakes of single wind turbines, Meneveau said. The new spacing model, he said, takes into account interaction of arrays of turbines with the entire atmospheric wind flow.

Meneveau and Meyers argue that the energy generated in a large wind farm has less to do with horizontal winds and is more dependent on the strong winds that the turbulence created by the tall turbines pulls down from higher up in the atmosphere. Using insights gleaned from high-performance computer simulations as well as from wind tunnel experiments, they determined that in the correct spacing, the turbines alter the landscape in a way that creates turbulence, which stirs the air and helps draw more powerful kinetic energy from higher altitudes.

The experiments were conducted in the Johns Hopkins wind tunnel, which uses a large fan to generate a stream of air. Before it enters the testing area, the air passes through an "active grid," a curtain of perforated plates that rotate randomly and create turbulence so that the air moving through the tunnel more closely resembles real-life wind conditions.

Air currents in the tunnel pass through a series of small three-bladed model wind turbines mounted atop posts, mimicking an array of full-size wind turbines. Data concerning the interaction of the air currents and the model turbines is collected by using a measurement procedure called stereo particle-image-velocimetry, which requires a pair of high-resolution digital cameras, smoke and laser pulses.

Further research is needed, Meneveau said, to learn how varying temperatures can affect the generation of power on large wind farms. The Johns Hopkins professor has applied for continued funding to conduct such studies.


Story Source:

The above story is based on materials provided by Johns Hopkins University. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins University. "Better turbine spacing for large wind farms." ScienceDaily. ScienceDaily, 7 February 2011. <www.sciencedaily.com/releases/2011/01/110120111332.htm>.
Johns Hopkins University. (2011, February 7). Better turbine spacing for large wind farms. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2011/01/110120111332.htm
Johns Hopkins University. "Better turbine spacing for large wind farms." ScienceDaily. www.sciencedaily.com/releases/2011/01/110120111332.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins