https://hdl.handle.net/20.500.11984/14090 2026-09-17T19:50:42Z 2026-09-17T19:50:42Z Zarketa-Astigarraga, Ander Manzanares Bercial, Raúl Martínez Cava, Alejandro Martin-Mayor, Alain Martinez Agirre, Manex Penalba, Markel https://hdl.handle.net/20.500.11984/14660 2026-09-06T06:15:46Z 2026-01-01T00:00:00Z

On the mitigation of detrimental effects via passive flow-control devices in aerodynamic airfoils operating under turbulence and surface degradation effects Zarketa-Astigarraga, Ander; Manzanares Bercial, Raúl; Martínez Cava, Alejandro; Martin-Mayor, Alain; Martinez Agirre, Manex; Penalba, Markel This work investigates how moderate turbulence and surface roughness jointly affect the aerodynamics of a NACA0021 airfoil operating at transitional Reynolds numbers (Re = 0.8–1.2×105). Wind-tunnel tests were performed under two controlled flow paradigms: a low-disturbance Clean condition and a Combined condition including both freestream turbulence (I ≈3.8%) and leading-edge roughness. In addition to the baseline (Bare) configuration, two unilateral passive-device layouts were tested, with triangular protrusions placed at x/c = 0.25 (PD25) and x/c = 0.5 (PD50). Results show that the Combined inflow linearises the lift curve and softens stall but reduces lift slope and aerodynamic efficiency by up to 60% compared with the Clean baseline. The effect of the passive devices depends on their position and on Re: PD25 can delay stall and recover efficiency at high angles of attack, while PD50 offers only limited or negative impact once the boundary layer becomes fully turbulent. Overall, the findings demonstrate that turbulence– roughness interactions dominate aerodynamic behaviour at transitional scales, and that small passive elements can provide only local improvements. These results underline the need to assess low-Re airfoils under realistic inflow conditions when developing flow-control strategies for distributed or urban wind-energy systems.

2026-01-01T00:00:00Z Nieto-Cerezo, Oscar Fernandez Mendoza, Joan Manuel https://hdl.handle.net/20.500.11984/14659 2026-09-06T06:15:44Z 2026-01-01T00:00:00Z

Circularity Governance Under Strategic Incentives: A Stackelberg Model of Wind Turbine Blade Recycling Nieto-Cerezo, Oscar; Fernandez Mendoza, Joan Manuel Circular economy goals under the European Green Deal require business models that make recyclability financially attractive, yet this alignment becomes fragile when eco-design effort is hidden and secondary-market prices are volatile. This paper develops a formal model of the wind-turbine blade (WTB) value chain to examine when closed-loop systems can internalise eco-design incentives. In a Stackelberg game between a manufacturer and a recycler, we show that reintegrating recovered glass fibre reinforced polymer (GFRP) into new WTBs can endogenously reward eco-design by linking material recovery to cost savings. However, this self-alignment weakens under risk aversion and competitive leakage, when recyclers divert material to more profitable external markets. We derive a robustness-adjusted subsidy threshold that ensures closed-loop stability and quantify how it varies with eco-design leverage, price uncertainty and technology choice. Numerical results for pyrolysis and solvolysis highlight how technological maturity and market risk shape feasibility.

2026-01-01T00:00:00Z Alberdi Orbegozo, Beñat Oyanguren, Aitor Ulacia, Ibai Larrañaga Amilibia, Jon https://hdl.handle.net/20.500.11984/14658 2026-09-06T06:15:45Z 2026-01-01T00:00:00Z

Effect of Roll Forming Process Imperfections on the Buckling Capacity of Racked Beams Alberdi Orbegozo, Beñat; Oyanguren, Aitor; Ulacia, Ibai; Larrañaga Amilibia, Jon Ensuring the stability and safety of steel storage racks is essential to withstand applied loads over time. Rack columns are typically produced through a cold roll-forming, enabling high productivity and open-section profiles, known as uprights. However, roll-forming imperfections can adversely affect buckling capacity. Stub column compression tests, as defined by the EN 15512 standard, experimentally determine the buckling capacity, while numerical methods further analyze it. A common way to introduce geometric imperfections in FEM models is by superposing scaled eigenmodes obtained from an elastic buckling analysis. Although standards specify imperfection types (local, distortional, global) and magnitudes, combining them remains unclear, often requiring multiple scenarios that may overly penalize capacity, as some imperfections rarely occur simultaneously. This work determines imperfection values from predefined roll-forming imperfections and identifies which combination most significantly affects open-section column buckling capacity. The initial roll-forming imperfections were measured and each amplitude established. A FEM model incorporating these imperfections was developed and validated against experimental data. Finally, the effects of these errors and their most critical combination on buckling capacity were determined, contributing to improved design procedures and a more reliable assessment of structural performance.

2026-01-01T00:00:00Z da Silva, Jorge Illarramendi, Miren Iriarte, Asier https://hdl.handle.net/20.500.11984/14657 2026-09-06T06:15:44Z 2023-01-01T00:00:00Z

Using Runtime Information of Controllers for Safe Adaptation at Runtime: A Process Mining Approach da Silva, Jorge; Illarramendi, Miren; Iriarte, Asier The increasing complexity of current Software Systems is generating the urge to find new ways to check the correct functioning of models during runtime. Runtime verification helps ensure that a system is working as expected even after being deployed, essential when dealing with systems working in critical or autonomous scenarios. This paper presents an improvement to an existing tool, named CRESCO, linking it with another tool to enable performing periodical verification based on event logs. These logs help determine whether the functioning of the system is inadequate or not after the last periodic check. If the system is determined to be working incorrectly, new code files are automatically generated from the traces of the log file, so they can be replaced when a faulty scenario is to occur. Thanks to this improvement, the CRESCO components are able to evaluate their correctness and adapt themselves at runtime, making the system more robust against unforeseen faulty scenarios.

2023-01-01T00:00:00Z