@article{Bertozzi2026b,

title = {Numerical analysis of a floating Airborne Wind Energy farm with a shared-mooring system},

author = {Andrea Bertozzi and Bruno Paduano and Francesco Niosi and Mattia Alborghetti and Lorenzo Fagiano and Giovanni Bracco},

doi = {https://doi.org/10.1016/j.apor.2026.105215},

issn = {0141-1187},

year  = {2026},

date = {2026-01-01},

urldate = {2026-01-01},

journal = {Applied Ocean Research},

volume = {174},

pages = {105215},

abstract = {Airborne wind energy (AWE) has the potential to complement conventional wind power and accelerate the transition to renewable energy. Realizing this potential will require offshore farm-scale deployments, where mooring systems represent a significant share of capital expenditures. Shared-line mooring concepts have been proposed to reduce these costs; however, floating AWE farms have not yet been studied, and shared-line designs have not yet been commercialized due to the complexity of mooring-induced platform-to–platform interactions. At the same time, taut mooring systems employing synthetic ropes are gaining interest, yet their inherently nonlinear behaviour is often neglected despite its known influence on system dynamics. This study addresses these gaps by numerically investigating the role of nonlinear tensile stiffness in shared-line moorings for floating AWE systems. A fully nonlinear stiffness model, based on industrial rope characteristics, is integrated to capture realistic material behaviour. The dynamics of a nine-platform shared-line farm are compared against a baseline single-device configuration under critical loading conditions, evaluating motions, line tensions, and hourly fatigue damage accumulation rate. Results show that even simple single-mooring configurations experience strong dynamic effects from material nonlinearities, including notable resonance shifts relative to linearized models. In shared-line arrangements, high-frequency load components associated with higher-order harmonics significantly accelerate fatigue damage accumulation. These findings underscore the critical importance of nonlinear mooring modelling in the design and assessment of shared-moored floating renewable energy systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wang2025,

title = {OC7 phase I: Toward practical sea-state-dependent modeling of hydrodynamic viscous drag and damping},

author = {Lu Wang and Amy Robertson and Jason Jonkman and Yingqian Liao and Petter Andreas Berthelsen and Serag-Eldin Abdelmoteleb and Peter Rohrer and Vishnu Ramachandran Nair Rajasree and Erin Bachynski-Polić and Constance Clement and Cédric Le Cunff and Prokopios Vlachogiannis and Christophe Peyrard and Dam Thanh Pham and Paul Leahy and Valérie Bouysses and Cédric Brun and Lizhong Wang and Lilin Wang and Long Teng and Wei Shi and Yushun Fu and Ali Abid and Zhengshun Cheng and Peng Chen and Zhirong Hu and Haozhe Bai and Kun Xu and Tuhin Das and Doyal Sarker and Tri Ngo and Pau Trubat Casal and Climent Molins and Francesco Niosi and Oronzo Dell'Edera and Bruno Paduano and Andrea Bertozzi and Giovanni Bracco and Bonaventura Tagliafierro and Abdolmajid Moghtadaei and Christopher Wright},

doi = {https://doi.org/10.1016/j.oceaneng.2025.121745},

issn = {0029-8018},

year  = {2025},

date = {2025-01-01},

urldate = {2025-01-01},

journal = {Ocean Engineering},

volume = {336},

pages = {121745},

abstract = {This article presents a collaborative research campaign under the OC7 project on refining the engineering modeling approach for hydrodynamic viscous drag and damping on floating wind platforms, focusing on the adjustment of hydrodynamic drag and damping coefficients for different sea states. The participant simulation results show significant improvements over the previous OC6 project in predicting the low-frequency resonance motion under nonoperational conditions. The improvements are mainly due to enhanced modeling, including the adoption of wave stretching, and directly tuning the coefficients to measured platform motion in waves instead of free decay. For accurate predictions of mean- and slow-drift motion, the better performing models use a decreasing column splash zone drag coefficient and increasing surge damping/drag with increasing wave height. The model tuning for heave and pitch resonance shows less consistency. Generally, both quadratic drag and additional heave or pitch damping are needed for accurate predictions. Alternatively, a quadratic drag formulation with velocity filtering for the rectangular pontoons leads to improved predictions without additional damping. This model is also potentially more predictive, requiring minimal adjustment to its parameters for different conditions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Bertozzi2024,

title = {Numerical Calibration of the Mooring System for a Semi-Submersible Floating Wind Turbine Model},

author = {Andrea Bertozzi and Francesco Niosi and Xiaoli Jiang and Zhiyu Jiang},

doi = {10.1115/1.4065551},

issn = {0892-7219},

year  = {2024},

date = {2024-01-01},

urldate = {2024-01-01},

journal = {Journal of Offshore Mechanics and Arctic Engineering},

volume = {146},

number = {6},

pages = {062001},

abstract = {Numerical modeling of the floating offshore wind turbine (FOWT) dynamics plays a critical role at the design stage of a floating wind project. Still, there exist challenges for verification of efficient engineering models against experimental results. Recently, an experimental campaign was carried out for a 1:96 downscaled model of the OC4-DeepCWind semi-submersible platform with mooring lines made of fiber ropes and chains. Leveraging the results of this campaign, this paper focuses on the development and calibration of a numerical model for the semi-submersible platform with a focus on the dynamic responses under bichromatic waves. In the numerical model, the hydrodynamic loads are modeled based on the potential flow theory with Morison drag. The lumped mass method is applied to model the mooring system. Both free decay tests and bichromatic wave conditions are considered in the model calibration process, and key uncertain parameters (e.g., mooring line length) that affect the response have been identified and discussed. Using the proposed calibration procedure, we establish a reasonably good numerical model for prediction of the platform motion and mooring dynamics. The low-frequency responses of the platform under bichromatic waves are well-captured. These outcomes contribute to the development of efficient numerical FOWT models under experimental uncertainty.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}