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
Failures in power grids: Dynamically induced cascades
25.05.2018 | Technische Universität Dresden
Beyond the limits of conventional electronics: stable organic molecular nanowires
24.05.2018 | Tokyo Institute of Technology
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences