Search NASA⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 3376224

OC7 Project Phase II: Code Comparison and Experimental Validation of Hydroelastic Effects and Member-Level Loads in Floating Structures

Bergua, R. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000347034729)·Carmo, L. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000187441391)·Jonkman, J. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000329907362)·Robertson, A. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000174484632)·Tessier, L. [Bureau Veritas Marine & Offshore (BVMO), Paris (France)]·de Lauzon, J. [Bureau Veritas Marine & Offshore (BVMO), Paris (France)]·Berdugo-Parada, I. [Centre Internacional de Mètodes Numèrics a l’Enginyeria (CIMNE), Barcelona (Spain)]·Garcia-Espinosa, J. [Universidad Politécnica de Madrid (UPM) (Spain)]·Servan-Camas, B. [Centre Internacional de Mètodes Numèrics a l’Enginyeria (CIMNE), Barcelona (Spain)]·Yu, J. [DNV, Shanghai (China)]·Rajasree, V. R. N. [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)]·Abdelmoteleb, S. -E. [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)]·Bachynski-Polić, E. [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)]·Niosi, F. [Marine Offshore Renewable Energy Laboratory (PLTO), Torino (Italy)]·Dell’Edera, O. [Marine Offshore Renewable Energy Laboratory (PLTO), Torino (Italy)]·Bracco, G. [Marine Offshore Renewable Energy Laboratory (PLTO), Torino (Italy)]·Nicolini, T. [PRINCIPIA, La Ciotat (France)]·Heurtier, J. M. [PRINCIPIA, La Ciotat (France)]·Cunff, C. Le [PRINCIPIA, La Ciotat (France)]·Cheng, Z. [Shanghai Jiao Tong Univ. (China)]·Shao, W. [Shanghai Jiao Tong Univ. (China)]·Zhou, W. [Shanghai Jiao Tong Univ. (China)]·Albers, M. [sowento GmbH, Stuttgart (Germany)]·Lemmer, F. [sowento GmbH, Stuttgart (Germany)]·Marten, D. [Technische Univ. Berlin (Germany)]·Rahman, S. [Univ. of Central Florida, Orlando, FL (United States)]·Sarker, D. [Univ. of Central Florida, Orlando, FL (United States)]·Ngo, T. [Univ. of Central Florida, Orlando, FL (United States)]
View original source ↗Read source document ↗Export metadata ↓

Abstract

This paper presents results from Phase II of the OC7 project, focusing on hydroelastic modeling and member-level load prediction for a flexible floating offshore structure. Numerical predictions from 11 academic and industrial partners are validated against experimental measurements obtained from a 1:70-scale test of the VolturnUS-S semisubmersible platform. A comprehensive set of verification and validation cases is examined. The results demonstrate that hydrodynamic added mass has a significant impact on predicted elastic natural frequencies. Under regular wave excitation, the numerical models reproduce platform motions and mooring line tensions with good accuracy. Member-level loads are also predicted with reasonable accuracy. Some discrepancies are observed for potential-flow models not accounting for higher-order effects associated with the instantaneous wetted surface.

Explore related subjects

17 WIND ENERGYOC7 projectfloating structureshydroelasticmember-levelvalidation

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Bergua, R. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000347034729), Carmo, L. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000187441391), Jonkman, J. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000329907362), Robertson, A. [National Laboratory of the Rockies (NLR), Golden, CO (United States). National Wind Technology Center] (ORCID:0000000174484632), Tessier, L. [Bureau Veritas Marine & Offshore (BVMO), Paris (France)], de Lauzon, J. [Bureau Veritas Marine & Offshore (BVMO), Paris (France)], Berdugo-Parada, I. [Centre Internacional de Mètodes Numèrics a l’Enginyeria (CIMNE), Barcelona (Spain)], Garcia-Espinosa, J. [Universidad Politécnica de Madrid (UPM) (Spain)], Servan-Camas, B. [Centre Internacional de Mètodes Numèrics a l’Enginyeria (CIMNE), Barcelona (Spain)], Yu, J. [DNV, Shanghai (China)], Rajasree, V. R. N. [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)], Abdelmoteleb, S. -E. [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)], Bachynski-Polić, E. [Norwegian University of Science and Technology (NTNU), Trondheim (Norway)], Niosi, F. [Marine Offshore Renewable Energy Laboratory (PLTO), Torino (Italy)], Dell’Edera, O. [Marine Offshore Renewable Energy Laboratory (PLTO), Torino (Italy)], Bracco, G. [Marine Offshore Renewable Energy Laboratory (PLTO), Torino (Italy)], Nicolini, T. [PRINCIPIA, La Ciotat (France)], Heurtier, J. M. [PRINCIPIA, La Ciotat (France)], Cunff, C. Le [PRINCIPIA, La Ciotat (France)], Cheng, Z. [Shanghai Jiao Tong Univ. (China)], Shao, W. [Shanghai Jiao Tong Univ. (China)], Zhou, W. [Shanghai Jiao Tong Univ. (China)], Albers, M. [sowento GmbH, Stuttgart (Germany)], Lemmer, F. [sowento GmbH, Stuttgart (Germany)], Marten, D. [Technische Univ. Berlin (Germany)], Rahman, S. [Univ. of Central Florida, Orlando, FL (United States)], Sarker, D. [Univ. of Central Florida, Orlando, FL (United States)], Ngo, T. [Univ. of Central Florida, Orlando, FL (United States)]. 2026-05-01. OC7 Project Phase II: Code Comparison and Experimental Validation of Hydroelastic Effects and Member-Level Loads in Floating Structures. https://doi.org/10.1088/1742-6596%2F3224%2F8%2F082024

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

An adaptive model-free robotic force control strategy for hydrodynamic real-time hybrid simulation of floating offshore wind turbines

Real-time hybrid simulation (RTHS) - a cyber-physical testing approach - promises to enhance the simulation fidelity of the model-scale experiments used to prototype floating offshore wind turbines (FOWTs). In hydrodynamic RTHS (hydro-RTHS), actuators emulate aerodynamic forces on model-scale FOWT specimens subjected to physical waves in a hydrodynamic laboratory. Robotic arms are promising candidates for actuation in hydro-RTHS due to their compact multi-degree-of-freedom (DOF) capabilities. Unlike classical RTHS for seismic applications, which typically relies on displacement control, hydro-RTHS requires 6-DOF force control on newly designed floating prototypes in a model-scale setting, which presents significant challenges, including modeling uncertainties, directional asymmetry, configuration drift, bandwidth limitations, and time-varying delays. To mitigate these constraints without extensive pre-test calibration, this study proposes an adaptive model-free robotic force control strategy that combines task-space explicit force control with a secondary joint-space pose-keeping task. The Adaptive Feedforward Compensator (AFC) is integrated into the force control loop to compensate for time-varying delay. Experimental testing was conducted using a Franka Emika Panda robotic arm with a 1:50 scale FOWT specimen under operational wind and wave conditions. Results demonstrate stable and consistent 6-DOF force tracking. Effective delay compensation was observed, with low-frequency delay reductions ranging from 71.4% to 91.8% and improvements in low-frequency surge force tracking of 25.0% to 52.1%. This study enhances robotic actuation performance in hydro-RTHS and introduces a force control strategy that supports reliable robotic operation in uncertain floating environments. Future work will explore disturbance-observer mechanisms to further enhance wave rejection capabilities under extreme wind and wave conditions.

17 WIND ENERGY↗
DOE OSTI2026

Computational capacity in hydrodynamic real-time hybrid simulation applied to simulate the dynamic response of floating offshore wind turbines

Real-time hybrid simulation (RTHS) mitigates similitude distortions in model-scale tests of floating offshore wind turbines (FOWTs) by coupling physical experiments with numerical models in real time. The coupling requires faster-than-real-time numerical computations to satisfy temporal similitude with the physical experiment, presenting a bottleneck for using more complex numerical models in RTHS. This paper presents a hydrodynamic-RTHS (hydro-RTHS) framework for FOWTs that simulates the hydrodynamics physically and the aerodynamics numerically with sensor feedback from the physical testing. The framework adapts the three-loop hardware architecture to leverage greater computational resources and mitigate strict temporal requirements, enabling more computationally demanding numerical analyses in hydro-RTHS. The three-loop hardware architecture integrates multiple machines, each dedicated to either numerical analysis or RTHS controls, with a rate-transition algorithm to synchronize the tasks executed across the different machine processors. Virtual and physical tests verified and validated the hydro-RTHS framework, respectively. The ”virtual” tests, which approximates the physical domain numerically, verified the RTHS framework with respect to a numerical full-scale complete FOWT model simulated in the open-source software, OpenFAST. The virtual tests were able to maintain comparable control signals while enabling greater computational resources for the numerical calculations. Real-world physical tests demonstrated that the hydro-RTHS framework computes aerodynamic forces similar to the complete OpenFAST model, validating the hydro-RTHS framework using the three-loop hardware architecture. Findings show that the hydro-RTHS framework with the three-loop hardware architecture is computationally efficient, with reserve capacity to simulate more complex problems due to the customized software, hardware, and rate-transition algorithm.

17 WIND ENERGY↗
DOE OSTI2026

Statistical Correlation of Heliostat Pointing Deviation With Wind

This work was carried out as part of the Heliostat Consortium (HelioCon) Field Deployment subtask with the aim to develop a reduced order model framework for correlating wind speed and pointing deviation of a heliostat facet. There are only sparse field measurements of heliostat pointing deviations and accompanying wind conditions published in the literature. Heliostat test standards, such as IEC 62862-4-3, propose a suite of tests including laser pointing repeatability at wind speeds below 4 m/s, and provide technical requirements for heliostat slope and tracking deviations in coarse average wind speed bins of 4 m/s, 6 m/s, and 8 m/s. In addressing the gap of the variation of heliostat pointing deviation with wind speed, field measurements of laser pointing on a grid target and wind conditions were analyzed in this study at the Third-Party Metrology Platform at the National Laboratory of the Rockies (NLR) Flatirons Campus. Horizontal pointing deviations were found to follow a logarithmic relationship with peak wind speed, whereas vertical pointing deviations follow an exponential relationship with peak wind speed. Both horizontal and vertical pointing deviations also follow a second order polynomial relationship, as expected from the proportionality of elastic loads and deformations with the square of wind speed. The results indicate that heliostat facet pointing deviations in the vertical direction increase at a faster rate than in the horizontal direction with increasing wind speed over the tested range, however these are dependent on the heliostat structural design. Next steps are recommended for additional field measurements to confirm a linear relationship of pointing deviation with applied moment on a heliostat facet, and to distinguish between gravity-induced and wind-induced pointing deviations at different elevation angles. The derived correlations in the preliminary analysis in this report serve as a case study for heliostat developers and plant operators to estimate the wind-induced pointing deviations and their variation with peak gust wind speed. Next steps in future work would recommend higher resolution and longer duration datasets for different elevation angles and wind directions to reduce uncertainties and variance of collected laser beam spot data and their correlations with bin-averaged wind speed.

17 WIND ENERGY↗