The work, published as a preprint under review in the journal Wind Energy Science by Hongwen Liu, Qingfu Song, Feng Guo, Lin Yang, Wenhao Xu, Lijun Zhang, and Zhen Gao, addresses a problem that has long frustrated wind turbine safety engineers. Full-scale blade-loss events are rare, dangerous, and almost impossible to instrument. When a blade does detach in the field, whether from fatigue, extreme loading, or a manufacturing defect, the consequences for the remaining two blades, the hub, the drivetrain, and the tower unfold in fractions of a second. Computer simulations can model these events, but without experimental data to validate them, engineers have no way of knowing whether their predictions of post-failure load redistribution are trustworthy.

The central challenge the researchers confronted is one of scaling consistency. When a turbine is shrunk by a factor of one hundred, the different physical forces acting on it do not shrink in the same proportion. Aerodynamic forces, which depend on air density, blade area, and the square of velocity, follow one scaling law. Centrifugal forces, which depend on mass, radius, and the square of rotational speed, follow another. Gravitational loads, tied directly to mass, follow a third. A naive scale model that simply miniaturizes the geometry will therefore distort the relative importance of these forces, potentially reproducing the wrong balance of loads entirely. The team’s solution was to establish common force and moment scales that simultaneously define coupled design targets for the rotor speed, the blade mass, the spanwise distribution of that mass along the blade, and the axial aerodynamic loading on the rotor.

This coupled approach means the model cannot be treated as a passive miniature. Every design parameter had to be adjusted in concert with the others so that when the model rotor spins and its blades experience aerodynamic, centrifugal, and gravitational loading, each of those load components maps back to the full-scale prototype through the same scaling relationship. Only then can a blade-detachment experiment on the model produce transient load measurements that are meaningfully transferable to the 10 MW onshore turbine that served as the prototype. The method, the authors report, was demonstrated on a 1:100 model of that machine, making it one of the most carefully constrained small-scale wind turbine replicas built for structural dynamics research.

Getting the aerodynamics right at such a small scale posed its own formidable difficulties. At one hundredth of full size, the air flowing over the model blades operates at very low Reynolds numbers, a dimensionless measure that combines flow speed, chord length, and air viscosity. At low Reynolds numbers, the boundary-layer behavior of air over a blade section changes dramatically, and lift and drag characteristics diverge from those of the full-scale airfoil. Rather than simply shrinking the prototype’s blade profiles, the team redesigned the blade geometry specifically for low-Reynolds-number operation, reshaping the aerodynamic sections so that the model blades generate the correct axial thrust when scaled up. This kind of redesign is essential if the aerodynamic contribution to the load transient is to match the prototype’s behavior during and after blade release.

The structural design of the model blades is equally ingenious. The researchers adopted a modular construction that combines a CNC-machined carbon-fibre spar with segmented segments of PMI foam, a rigid polymethacrylimide foam commonly used as a lightweight structural core. This modularity serves two purposes. First, it allows the aerodynamic outer profile of the blade to be adjusted independently of the internal material distribution, decoupling two design variables that would otherwise be locked together. Second, it permits the spanwise mass distribution along the blade to be tuned precisely, which is critical because the centrifugal load a blade section experiences depends directly on how much mass sits outboard of it. By machining the spar and shaping the foam segments separately, the team could satisfy the coupled scaling targets for both mass distribution and aerodynamic loading without compromising either.

To verify that the model actually behaves as intended, the researchers conducted centrifugal-load and aerodynamic-load experiments under the tested conditions and compared the measurements against numerical predictions. The results showed overall agreement between the simulations and the experimental data, an encouraging sign that the scaling method captures the essential physics rather than producing a model that merely looks right. That agreement matters because the entire purpose of the exercise is validation: the model is intended to serve as a physical testbed whose measurements can be used to check and refine computer models of how loads redistribute across a damaged turbine in the moments after a blade departs.

The implications extend well beyond a single laboratory demonstration. With a validated 1:100 platform in hand, researchers can now design controlled blade-release experiments in which detachment is triggered deliberately and instrumented comprehensively, something that could never be done on an operating 10 MW turbine. Such experiments would generate transient load data covering the aerodynamic, centrifugal, and gravitational components simultaneously, providing exactly the kind of multi-physics benchmark that numerical models of post-failure dynamics have lacked. Better-validated models, in turn, would help engineers assess the loads that surviving structures must withstand after a blade-loss event, informing everything from emergency shutdown strategies to the design of towers and hubs with greater damage tolerance.

The timing of this research is significant for the wind energy industry. As turbines grow ever larger, with offshore machines now exceeding 15 MW and rotor diameters stretching beyond 250 meters, the consequences of structural failure grow correspondingly severe. Blades operate under enormous cyclic stresses for decades, and while catastrophic detachment remains rare, the industry’s expansion into deeper waters and harsher environments increases the premium on understanding worst-case structural scenarios. A scaled experimental platform that faithfully reproduces load transients offers a comparatively inexpensive and entirely safe route to stress-test the simulation tools that certification bodies and operators rely upon when assessing structural integrity.

What makes this study particularly compelling is its methodological generality. Although demonstrated on a 10 MW onshore prototype, the design method itself, establishing common force and moment scales to derive coupled targets across rotor speed, blade mass, mass distribution, and aerodynamic loading, is not tied to any single machine. The same framework could, in principle, be applied to scale models of larger offshore turbines or floating platforms, where blade-loss dynamics interact with platform motions in ways that are even harder to study at full scale. As the authors note, the resulting model provides an experimental basis for controlled blade-detachment testing and subsequent validation of numerical models of post-failure load redistribution. In a field where the difference between a well-predicted failure and a poorly predicted one can determine whether a damaged turbine survives its final minutes, that experimental basis may prove to be one of the most quietly consequential contributions to wind turbine safety in years.

Subject of Research: Scaled wind turbine model design for reproducing structural load transients during blade detachment

Article Title: Design of a scaled wind turbine model for matching multiple structural load transients under blade-detachment conditions

Article References: Liu, H., Song, Q., Guo, F., Yang, L., Xu, W., Zhang, L., & Gao, Z. (2026). Design of a scaled wind turbine model for matching multiple structural load transients under blade-detachment conditions. https://doi.org/10.5194/wes-2026-167

Image Credits: AI Generated

DOI: 10.5194/wes-2026-167

Keywords: wind turbine, blade detachment, scaled model testing, structural load transients, aerodynamics, centrifugal load, load redistribution, wind energy, model validation, 10 MW turbine, low Reynolds number, carbon-fibre spar