06 Fakultät Luft- und Raumfahrttechnik und Geodäsie
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/7
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Item Open Access Messungen im Bereich eines Windparks mit Fokus auf tief- und niederfrequente Schallemissionen und -immissionen(2022) Blumendeller, Esther; Gaßner, Laura; Müller, Florian; Wigger, Maayen; Berlinger, Philipp; Cheng, Po WenDie Nutzung von Windenergie wird einen entscheidenden Anteil am erneuerbaren Energiemix der Zukunft haben. Während der Stromgewinnung geben Windenergieanlagen (WEA) Schall und Erschütterungen (seismische Wellen) in die Umgebung ab, vor allem im tieffrequenten Bereich. Im Zuge des interdisziplinären Verbundprojektes Inter-Wind werden akustische Messungen zur Unterstützung psychologischer Fragebögen, kombiniert mit seismischen und meteorologischen Messungen an Windparks auf der Schwäbischen Alb durchgeführt. Ziel des Projektes ist es, die Gründe für Belästigung der Anwohner in Zusammenhang mit den Immissionen der WEA zu verstehen. Hierbei liegt der Fokus auf dem tieffrequenten (20-200 Hz) und niederfrequenten (1-20 Hz) Bereich. Akustische und seismische Messungen wurden an einem Windpark auf der Schwäbischen Alb, mit drei WEA des Typs GE 2.75-120 durchgeführt. Parallel dazu konnten Anwohner Belästigungszeiträume über eine Geräuschmelde-App dokumentieren. In diesem Beitrag wird die Umsetzung einer interdisziplinären Messkampagne im Bereich des Tegelberg Windparks und eines Wohngebäudes in Tallage in ca. 1 km Entfernung zum Windpark beschrieben. Schließlich werden erste Ergebnisse der akustischen Messungen und interdisziplinären Untersuchung vorgestellt und diskutiert.Item Open Access Acoustic and seismic emissions from wind turbines(2017) Calarco, Francesca; Cheng, Po Wen; Zieger, Toni; Ritter, JoachimWith regards to the interdisciplinary “TremAc” Project funded by the German Federal Ministry for Economic Affairs and Energy, this paper examines acoustic and seismic emissions generated by wind turbines with the aim of identifying a better understanding of their interaction. Measurement campaigns will be carried out in the field around a single wind turbine plant and results in terms of acoustic and seismic signals will be correlated and then evaluated in relation to environmental factors such as wind speed, wind direction and temperature as well as to data related to the wind turbines-specifications (e.g. rotation speed).Item Open Access FlexDyn - a new OpenFAST structural dynamics module for a general, user defined wind turbine topology(2021) Lemmer, Frank; Pérez Brovia, Santiago; Skandali, Danai; Raach, SteffenIn the present work, FlexDyn, a new structural dynamics module for the OpenFAST framework is developed. FlexDyn can generate structural equations of motion through a formalism, given user-defined rigid and elastic bodies and associated Degrees of Freedom (DOFs). The Newton-Euler formalism uses beam models with shape functions for a reduced-order representation in the same way as ElastoDyn of OpenFAST. The equations of motion are formulated in minimal coordinates, equally to ElastoDyn. FlexDyn is fully integrated into the OpenFAST framework with a coupling to AeroDyn and the new SubDyn module for FE representations of floating substructures (Jonkman, et al., 2020), among others. The formalism was previously implemented and verified in the low-order aero-hydro-servo-elastic code SLOW (Lemmer, et al., 2020). The objective of the presentation is to show the methodology of the formalized generation of equations of motion and first results of the new FlexDyn module for OpenFAST. The use case is an improved aero-elastic model, which includes the torsional DOF of the blades. The torsional DOF is not included in the ElastoDyn module but can potentially contribute to the motion and load response of the blades. The fidelity level of this use case of FlexDyn is higher than that of ElastoDyn but still below that of BeamDyn, which is a full FE representation of the blades. For this reason, the computational performance is still in the range of ElastoDyn, taking advantage of the order reduction.Item Open Access Load sensitivity analysis for a floating wind turbine on a steel semi-submersible substructure(2018) Müller, Kolja; Faerron Guzman, Ricardo; Cheng, Po Wen; Galván, Josean; Sánchez Lara, Miren; Rodríguez Arías, Raúl; Manjock, AndreasThe site-specific load verification for floating offshore wind turbines requires the consideration of the complex interaction of the different system components and their environment. Sensitivity analyses help reducing the simulation amount for both fatigue and ultimate load analysis significantly by highlighting relevant load parameters and increase the understanding for the system behavior in its real environment. Aligned with work in the H2020 project LIFES50+, this study investigates different approaches for global sensitivity analysis using quasi-random sampling for the independent variables. Two different load case groups are analyzed: (1) fatigue loads during power production, (2) ultimate loads during power production and severe sea state. The considered system is the public DTU 10MW turbine’s rotor-nacelle assembly, installed on the public NAUTILUS-10 floating structure. Load simulations are performed by using FAST v8. Simulations are set up based on the LIFES50+ Site B (medium severity). A comparison is made to a similar study with a different platform (Olav Olsen semi-submersible) in order to observe if similar conclusions can be reached for the different floater types.Item Open Access Multi-variable feedforward control for floating wind turbines using lidar(2020) Schlipf, David; Lemmer, Frank; Raach, SteffenIn this work a multi-variable feedforward controller for floating wind turbines is presented. The feedforward controller provides a pitch rate and a torque update to a conventional feedback controller based on a wind speed preview. A 10 MW reference wind turbine is used on a semi submersible floating platform to study the potential of the controller. An open-source simulation tool is extended with an realistic lidar simulator and the lidar data processing, feedforward controller, and feedback controller are implemented in modular setup. The lidar measurements are fully motion compensated and combined to provide a preview of the rotor-effective wind speed to the controller. The feedforward controller is designed to minimize structural loads and to decrease the platform pitch motion. In verification and simulation studies the concept is demonstrated and the multi-variable feedforward controller shows a promising improvement in speed regulation and load reduction on the floating wind turbine.Item Open Access Advances on reduced-order modeling of floating offshore wind turbines(2021) Lemmer, Frank; Yu, Wei; Steinacker, Heiner; Skandali, Danai; Raach, SteffenAero-hydro-servo-elastic modeling of Floating Offshore Wind Turbines (FOWTs) is a key component in the design process of various components of the system. Different approaches to order reduction have been investigated with the aim of improving structural design, manufacturing, transport and installation, but also the dynamic behavior, which is largely affected by the blade pitch controller. The present work builds on previous works on the SLOW (Simplified Low-Order Wind Turbine) code, which has already been used for the above purposes, including controller design. While the previous rigid rotor model gives good controllers in most cases, we investigate in the present work the question if aero-elastic effects in the design model can improve advanced controllers. The SLOW model is extended for the flapwise bending and coupled to NREL's AeroDyn, linearized and verified with the OlavOlsen OO-Star Wind Floater Semi 10MW public FOWT model. The results show that the nonlinear and linear reduced-order SLOW models agree well against OpenFAST. The state-feedback Linear Quadratic Regulator (LQR) applied with the same weight functions to both models, the old actuator disk, and the new aero-elastic model shows that the LQR becomes more sensitive to nonlinear excitation and that the state feedback matrix is significantly different, which has an effect on the performance and potentially also on the robustness. Thus modeling uncertainties might even be more critical for the LQR of the higher-fidelity model.Item Open Access The TripleSpar campaign: validation of a reduced-order simulation model for floating wind turbines(2018) Lemmer, Frank; Yu, Wei; Cheng, Po Wen; Pegalajar-Jurado, Antonio; Borg, Michael; Mikkelsen, Robert F.; Bredmose, HenrikDifferent research groups have recently tested scaled floating offshore wind turbines including blade pitch control. A test conducted by the University of Stuttgart (Germany), DTU (Denmark) and CENER (Spain) at the Danish Hydraulic Institute (DHI) in 2016 successfully demonstrated a real-time blade pitch controller on the public 10MW TripleSpar semisubmersible concept at a scale of 1/60. In the presented work a reduced-order simulation model including control is compared against the model tests. The model has only five degrees of freedom and is formulated either in the time-domain or in the frequency-domain. In a first step the Morison drag coefficients are identified from decay tests as well as irregular wave cases. The identified drag coefficients depend clearly on the sea state, with the highest ones for the decay tests and small sea states. This is an important finding, for example for the design of a robust controller, which depends on the system damping. It is shown that the simplified model can well represent the dominant physical effects of the coupled system with a substantially reduced simulation time, compared to state-of-the-art models.Item Open Access Validation of INNWIND.EU scaled model tests of a semisubmersible floating wind turbine(2016) Koch, Christian; Lemmer, Frank; Borisade, Friedemann; Matha, Denis; Cheng, Po WenThe subject of this study is the verification and the validation of existing numerical codes for floating offshore wind turbine structures using wave tank model tests as part of the INNWIND.EU project. A model of the OC4-DeepCwind semisubmersible platform, together with a Froude scaled rotor model with low-Reynolds airfoils is tested in a combined wind-and-wave basin. The simulation environment comprises the multibody software SIMPACK with the HydroDyn module for the hydrodynamic loads, MAP++ for the mooring line forces and AeroDyn for the aerodynamic loads. The focus of this paper is the validation of the hydrodynamics of a modified model hull shape, which compensates for the excess mass of the nacelle. Furthermore also first steady wind simulations without wave excitation have been carried out. The results show that the model is validated and gives the basis for further research based on the conducted experiments.