Sharp edge improves aerodynamics of rotor blades

13.06.2025

Source: E & M powernews

A project at Kiel University of Applied Sciences for the aerodynamic optimization of rotor blades also enables an increase in performance for existing turbines. New rotor blades deliver four percent more.

Small changes to the shape of rotor blades enable a large increase in performance. This is the result of a research project at Kiel University of Applied Sciences. The team led by project manager Professor Alois Schaffarczyk worked on the aerodynamic optimization of the rotor blades of mega wind turbines. In cooperation with the company Deutsche Windguard Engineering from Varel and Aerovide from Rendsburg, the researchers examined a rotor blade in the ten megawatt class.

The hub height of these turbines is over 140 meters, the diameter of the rotors from one tip to the other is around 200 meters and the rotor blades are more than 90 meters long. The area investigated by the team concerns the inner 15 meters of the rotor, according to the project manager. Schaffarczyk: "With such dimensions, even small changes can enable a large increase in effective performance." The researchers developed a specially manufactured rotor trailing edge that reduces the resistance in the inner part of the blade.

Four percent more power yield

"All calculations and also the tests in the wind tunnel have shown that we can increase the performance of the turbine by up to four percent in this way," said Schaffarczyk. The team also used additional aerodynamic aids, which can be retrofitted during maintenance work, for example, and also increase performance. This makes it possible to increase the electricity yields from offshore wind power, even from existing turbines.

The German Federal Environmental Foundation (DBU) has funded the research at Kiel University of Applied Sciences with around 235,000 euros. DBU Secretary General Alexander Bonde named an "ecologically compatible expansion of wind farms" and the "optimization of wind turbines through innovative technologies" as the goal.

Greater effectiveness as a piece of the energy transition puzzle

Increasing the effectiveness of existing technologies is an important contribution to achieving the expansion targets, the project manager emphasized. This is an "important piece of the energy transition puzzle". The researchers have made the results of their investigations freely available online. The company Aerovide is planning to apply the innovative design. According to the company, it has already been integrated into a rotor blade as part of a commercial concept study in order to carry out a complete system simulation.

According to the German Wind Energy Association (BWE), a total of 1,639 wind turbines with a total capacity of 9,200 MW were installed in German territorial waters in the North Sea and Baltic Sea at the end of 2024. The expansion targets envisage installing at least 30,000 MW of offshore capacity by 2030, at least 40,000 MW by 2035 and at least 70,000 MW by 2045. According to the German Offshore Wind Energy Association (BWO), this could generate around 220 billion kWh of electricity per year from 2045. This corresponds to half of Germany's electricity consumption in 2024.

The results of the Kiel University of Applied Sciences study are available on the Internet.

Author: Susanne Harmsen