The turbine tower was just 10 inches high. Its three blades were 10 inches in diameter. It was a perfect 1:320 scale reproduction of the 80-meter diameter wind turbines spinning across Iowa, the country’s second-ranked state in installed wind power capacity.
That mini turbine is helping a research team led by Hu, an Iowa State University associate professor of aerospace engineering, understand how hills, valleys and the placement of turbines affect the productivity of onshore wind farms.
While the wind industry has data about offshore turbine performance over flat water – especially from European studies – Hu said there’s little data about the effects of uneven ground on wind turbines.
And so Hu and his research team have created the mini turbines and started running tests in Iowa State’s $1.25 million Aerodynamic/Atmospheric Boundary Layer Wind and Gust Tunnel.
“We want to work with the wind turbine industry to transfer some of our findings,” Hu said. “We can help boost total energy capture. And we can lengthen the lifetimes of wind turbines, making them more efficient.”
The research team led by Hu includes Richard Wlezien, professor and Vance and Arlene Coffman Endowed Chair in Aerospace Engineering; Partha Sarkar, a professor of aerospace engineering, of civil, construction and environmental engineering, and director of Iowa State’s Wind Simulation and Testing Laboratory; Zifeng Yang, a former Iowa State post-doctoral researcher and now an assistant professor at Wright State University in Dayton, Ohio; Wei Tian, a post-doctoral research associate in aerospace engineering; and Ahmet Ozbay, a graduate student in aerospace engineering.
The engineers’ studies are supported by a three-year, $300,000 grant from the National Science Foundation and a two-year, $100,000 grant from the Iowa Alliance for Wind Innovation and Novel Development.
The researchers are using wind tunnel tests to quantify the characteristics of surface winds over hilly terrains, determine the best placement of wind turbines on hilly terrains and find the best design for large wind farms on hilly terrains.
• Mini generators mounted inside the mini turbine nacelles measure power production
• Sensors mounted at the base of the mini turbines measure the wind loads placed on turbines and turbine towers
• Advanced flow measurements such as particle image velocimetry (which uses a laser and camera to take nearly simultaneous images that show the movement and velocity of individual particles) to measure wind flow fields, the wind vortices created by the tips of turbine blades and the total wind energy captured by the blades.
Hu said preliminary results indicate that wind turbines on hilly terrain are hit with much higher wind loads than turbines on flat terrain. The experiments also show that, compared with turbines on flat ground, wind flowing over hilly terrain recovers its power potential more rapidly as it moves from turbine to turbine.
Data from the wind tunnel indicate a turbine on flat ground in the wake of another turbine at a distance equal to six times the diameter of the turbines loses 13 percent of power production. A turbine in the wake of another with the same downstream distance on hilly ground loses 3 percent of power production.
“That means you can put wind turbines closer together in hilly terrain,” he said.
In November, Hu, Yang and Sarkar published the first paper about their wind-turbine studies – “Visualization of the tip vortices in a wind turbine wake” on the Journal of Visualization’s website. The three researchers also presented findings of their turbine wake studies at the June 2011 Applied Aerodynamics Conference of the American Institute of Aeronautics and Astronautics.
The project’s next steps include building a nine-turbine array in Iowa State’s big wind tunnel to study power production and wind flows through a mini wind farm.
Hu is confident that data from the experiments can be valuable as more and more wind farms are built across Iowa and the country.
“These studies are telling us things we didn’t know before,” Hu said. “And this will help optimize the design of wind turbine layouts with consideration of the terrain.”
Mike Krapfl | Newswise Science News
Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH
Engineers find better way to detect nanoparticles
14.08.2017 | Washington University in St. Louis
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy