For a motorized hangglider or a one-seater weighing 300 kilograms: the business of flying by ultra-light aircraft is booming. That is also why numerous airfields are applying for the license to host these lightweight gliders. Most of these airfields are located on flat land, which is also the preferred terrain for wind power plant.
The simulation reveals the turbulence generated by wind turbines. The red beam indicates heavy turbulence – which is particularly common behind the wind power plant.
© Fraunhofer IWES
However, these facilities could turn out to be a risk factor for aviators, especially when it comes to takeoff and landing: On the one hand, the power plants “pilfer” the winds from the planes, because wind speeds aft of such facilities are considerably lower. If the aircraft fly in the region behind the rotor, then they will suddenly find themselves contending with an entirely new aerodynamic situation. On the other hand, rotors produce turbulence in the air that could equally interfere with the aircraft.
Simulation calculates turbulence
The extent to which wind turbines impact ultra-light aircraft is an especially pertinent question now at the Linnich-Boslar ULV Airfield, where a major wind farm is slated for construction in close proximity. The operator, BMR Windenergie, wants to be sure – prior to construction – that no risk imperils the aviators. On behalf of this company, researchers at the Fraunhofer Institute for Wind Energy and Energy System Technology IWES in Oldenburg developed a simulation that enables them to calculate what turbulence these facilities generate, how they alter wind speed and what influence these factors have on airplanes.
“We conducted these simulations under a variety of scenarios,” says Dr. Bernhard Stoevesandt, head of department at IWES. “We simulated various wind directions, two different wind speeds and five different flight trajectories in which the plane is under the rotor’s sphere of influence for various lengths of time.”
Complex grid model
For the simulations, the researchers initially created a computer model of the ground and a wind profile of the surrounding area where the wind farm is to be built. A grid was placed over the model. The computer calculates how the power plants alter wind conditions and turbulence at various points on the grid. “The true skill is in the creation of the grid: Because the points on the grid where the computer makes the individual calculations must lie at exactly the right places,” explains Stoevesandt.
The complexity of the simulation is enormous – the software must calculate the prevailing currents within several million grid cells that mutually influence each other. Other challenges consist in properly depicting the trail – that is, the turbulence and the change in wind speed behind the rotor – and determining how it affects the airplane. “To validate the simulations, the trail from actual wind energy plants was measured at various individual points behind the rotor, and the measurements compared with the simulations,” affirms Stoevesandt. “Each of the data matched well.”
Altogether, the scientists examined the effects of wind farms within an approximately 1500 meter perimeter and an altitude of up to 500 meters. By comparison, the hub of the rotor is 123 meters in height. The finding: At the Linnich-Boslar landing field, the turbulence generated by the wind turbines is lower than the ordinary turbulence of the surrounding environment. Still, this finding can only be applied to other airports to a limited extent, because the surrounding terrain has a tremendous impact on the trail; unlike flat terrain, the trail is different where the landscape is forested or hilly. “The simulations would have to be commensurately adjusted for those kinds of airfields,” says Stoevesandt.
Dr. rer. nat. Bernhard Stoevesandt | Fraunhofer Research News
A big nano boost for solar cells
18.01.2017 | Kyoto University and Osaka Gas effort doubles current efficiencies
Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences