Holey Airhead The Aviation of the Future Works (Almost) Without Air Friction Losses

In the SE²A Excellence Cluster at the Technical University of Braunschweig (Germany), wings have been successfully made more aerodynamic and thus more efficient through 3D printing. These are the advantages ...

As early as 2024, researchers from the SE2A Excellence Cluster in collaboration with the German Aerospace Center (DLR) demonstrated the possibilities of 3D-printed panels for boundary layer suction in the wind tunnel. It was proven that it is possible to achieve a so-called laminarization of the boundary layer with micro-perforated—that is, equipped with tiny holes—suction panels from the 3D printer. A small part of the boundary layer is suctioned off through the micro-perforated surface and thus stabilized, the experts explain. Now, for the first time, researchers Lajos Fohlmeister and Jan Kube have succeeded in generating a laminar boundary layer on a 3D wing using integrated 3D-printed suction panels.

90 Percent Less Air Friction When Flying

With the new suction panels, the boundary layer on aerodynamic bodies can be altered in such a way that the laminar-turbulent transition is shifted further downstream. The proportion of the laminar boundary layer is thus significantly increased. The advantage is that the laminar boundary layer causes up to 90 percent less air friction than the turbulent boundary layer, according to the researchers. This is beneficial because air friction accounts for about half of the total resistance that modern commercial aircraft must constantly overcome. Laminar flow control is therefore a promising way to significantly reduce the fuel consumption—and thus the emissions—of commercial aircraft. For the printers, manufacturing the particularly fine micro-perforation with a diameter of less than 250 micrometers was indeed a real challenge.

Special Wing Geometry Aids Research

A particular highlight of the new study is also the 3D sickle wing, developed at the Institute of Fluid Mechanics in the Excellence Cluster. The special geometry, in the shape of a sickle, allows the investigation of different aerodynamic states and, in particular, the transitions between these states. The sickle wing was designed to simulate a newly designed airfoil profile under realistic conditions. The insights gained in this way also contribute to improving numerical methods for predicting different transition scenarios—namely the laminar-turbulent transition of the boundary layer—according to the participants. The work is not only attractive for commercial aircraft but also for designers of sailplanes and light aircraft.

More Information About the SE²A Excellence Cluster

The Excellence Cluster "Sustainable and Energy Efficient Aviation" (SE²A) is addressing the challenge of making future air traffic efficient while meeting the competing demands for continuous growth and ecological sustainability. In addition to the Technical University of Braunschweig, the DLR, Leibniz University Hannover, the University of Fine Arts Braunschweig, and the Physikalisch-Technische Bundesanstalt (all located in Germany) are involved. The Excellence Cluster is part of the joint research focus "Mobility" at the Technical University of Braunschweig.

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