https://hdl.handle.net/20.500.11984/473 2026-09-17T19:50:41Z https://hdl.handle.net/20.500.11984/14660 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 https://hdl.handle.net/20.500.11984/14659 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 https://hdl.handle.net/20.500.11984/14655 Ander Manterola Aldekoa: zeanuriztar etnografoari elkarrizketa Mentxakatorre Odriozola, Jon 2025-11-30T00:00:00Z https://hdl.handle.net/20.500.11984/14654 Battery aging-aware adaptive model predictive control based on coupled semi-empirical electro-thermal and aging models Dorronsoro, Xabier; de Castro, Ricardo; Barreras, Jorge Varela; GARAYALDE, ERIK; IRAOLA, UNAI This paper presents an aging-rate aware nonlinear model predictive control (MPC) strategy for battery energy storage systems, integrating a semi-empirical, experimentally validated electro-thermal and degradation model to account for both calendar and cycle aging factors, often neglected in conventional energy management approaches. A key contribution is the introduction of a adaptive weighting method that dynamically adjusts the weights of the MPC cost function according to the battery’s aging state, primarily driven by time-dependent degradation factors. This adaptive mechanism improves control decisions across varying prediction horizons, leading to reductions in both battery degradation and total operating costs by up to 262.7 % and 44.51 %, respectively, when compared to a standard MPC. 2025-01-01T00:00:00Z