Christian Bak is appointed Professor in rotor aerodynamics for wind turbines at DTU Wind and Energy Systems. He is Head of Section for Airfoil and Rotor Design and heading the new Poul la Cour Wind Tunnel at the DTU Campus at Risø which is dedicated to research in wind energy. The appointment to Professor means a clearer profiling of his interests which are research in rotor aerodynamics for wind turbines.
The work with the wind tunnel is one of Christian Bak's greatest interests, but the newly minted professor is passionate about many aspects of the job at DTU Wind and Energy Systems. "What makes going to work fun is a combination of many aspects", he says and elaborates: "Measurements in the wind tunnel and on full-size wind turbine blades, for example, are very interesting because here we can tell whether the modelling, we make on the computer, matches reality", says Christian Bak.
The connection between basic research to the design of full scale wind turbine rotors and thus the production of wind energy has been a common thread throughout Christian Bak's career. Since he started his career in 1997 at Risø, he has come far and wide in research into aerodynamics. Of milestones, he highlights the work of calculating wind flows on wind turbine blades. Here he has, among other things, designed airfoils that are used in wind turbine blades from major Danish and international wind turbine manufacturers. Moreover, he was part of making the first detailed aerodynamic measurements on a multi megawatt wind turbine – the so-called DANAERO MW test campaign – in co-operation with four industrial partners.
Christian Bak has taken part of investigations of various concepts for rotor design, too, and he is a co-inventor of active trailing edge flaps for wind turbine blades. Part of the research takes place on DTU's digital 10 megawatt wind turbine which he had the responsibility of designing. According to Christian Bak, it is not "too far" from a real wind turbine so, it is used for Danish and international research in dynamics of wind turbines.
The Poul la Cour wind tunnel
Christian Bak's greatest achievement is creating the Poul la Cour wind tunnel. The realization of the wind tunnel began in 2011 and was completed in 2018 and Christian Bak had the technical responsibility all the way, and today he is Head of the wind tunnel today. Here, too, he has worked from a conviction that the research infrastructure has got to be used widely. Consequently, many stakeholders from universities and the wind turbine industry were consulted during the design process of the wind tunnel. "The extensive use of the wind tunnel – including the use of the industry – is very satisfying”, he says.
Collaboration across research fields
A major field of interest for both researchers and wind turbine manufacturers is erosion of wind turbine blades, which is a significant challenge in the industry. Over time, wind turbine blades can become rough, which costs energy production. Here, Christian Bak, together with good colleagues, is in the process of understanding the role of erosion in connection with aerodynamics of the blades. In fact, research into erosion of wind turbine blades goes across all four research fields at DTU Wind and Energy Systems which apart from aerodynamics also concerns materials and meteorological conditions.
Cross-disciplinary collaboration is no stranger to Christian, who attaches great importance to communication. Among other things, he has developed teaching materials for lessons in rotor aerodynamics over the years, because: "It is important to make the research understandable for the students, as they are the researchers and wind turbine designers of the future", concludes Christian Bak.
Christian Bak will give an inaugural lecture on 25 November 2022 at 14.00 at DTU Lyngby campus in building 101, meeting room 1. The lecture will be followed by a reception.
