The Effect of Counterweight Mass and Line Stiffness on the Global Dynamic Performance of a Hanging-Mass Floating Offshore Wind Turbine

2021 ◽  
pp. 1-15
Author(s):  
Jacob Ward ◽  
Andrew J. Goupee ◽  
Anthony M. Viselli ◽  
Habib Dagher
Keyword(s):  
Wind Turbine ◽  
Parametric Study ◽  
Strong Influence ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Linear Wave ◽  
Energy Potential ◽  
Floating Offshore Wind Turbine ◽  
Study Results ◽  
Multi Body

Abstract Innovative floating offshore wind turbine (FOWT) platforms that deviate from the conventional semi-submersible, spar, and tension leg platforms (TLP) have become increasingly common due to the need to tap into the high wind energy potential located in deeper waters. One example is the hanging-mass concept, in which a suspended counterweight stabilizes a positively buoyant floater. This work presents a two-dimensional, nonlinear, multi-body model used to assess the influence of the counterweight mass and the suspension line stiffness on the system's global performance, using linear stability analysis and time-domain simulations to conduct a parametric study. For example, the counterweight mass has a strong influence on the amplitude of rotational degrees of freedom. Corresponding natural periods may occur within the linear wave energy range for suitable counterweight sizes due to this strong influence leading to undesirable motions. High-frequency multi-body modes are also dependent on both the line stiffness and counterweight mass, which may result in high relative motion amplitudes and slack lines in certain conditions. Finally, the parametric study results contribute to preliminary hanging-mass FOWT design recommendations.

Investigation on High-Order Coupled Rigid-Flexible Multi-Body Dynamic Code for Offshore Floating Wind Turbines

2017 ◽  
Author(s):  
Zhiqiang Hu ◽  
Jiahao Chen ◽  
Geliang Liu
Keyword(s):  
Wind Turbine ◽  
Coupled Model ◽  
High Order ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Mooring Lines ◽  
Simulation Code ◽  
Floating Offshore Wind Turbine ◽  
Restoring Forces ◽  
Multi Body

This paper presents a preliminary development and validation of a high-order coupled time-domain simulation code DARwind for floating offshore wind turbine systems. In the code, unsteady Blade-Element-Momentum method with some corrections has been utilized to calculate aerodynamic loads. Combination of potential-flow theory and Morison“s equation are applied to calculate hydrodynamic loads. A quasi-static catenary mooring model is used to consider restoring forces from mooring lines. Kane“s dynamic equations and a high-order coupled model with mode superposition are proposed to model kinematics and structural dynamics of floating offshore wind turbine systems. Subsequently, the effectiveness of the code and its unique high-order coupled dynamic characteristics have been verified by code-to-code tests.

Coupled Analysis of a 10 MW Multi-Body Floating Offshore Wind Turbine Subjected to Tendon Failures

2021 ◽  
Author(s):  
Yang YANG ◽  
Musa BASHIR ◽  
Constantine MICHAILIDES ◽  
Xuan MEI ◽  
Jin WANG ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Offshore Wind ◽  
Coupled Analysis ◽  
Offshore Wind Turbine ◽  
Floating Offshore Wind Turbine ◽  
Multi Body

scholarly journals Resonance Avoidance Control Algorithm for Semi-Submersible Floating Offshore Wind Turbine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4138
Author(s):  
Kwansu Kim ◽  
Hyunjong Kim ◽  
Hyungyu Kim ◽  
Jaehoon Son ◽  
Jungtae Kim ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Control Algorithm ◽  
Torque Control ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Resonance Problem ◽  
Exclusion Zone ◽  
Mean Power ◽  
Floating Offshore Wind Turbine ◽  
Avoidance Control

In this study, a resonance avoidance control algorithm was designed to address the tower resonance problem of a semi-submersible floating offshore wind turbine (FOWT) and the dynamic performance of the wind turbine, floater platform, and mooring lines at two exclusion zone ranges were evaluated. The simulations were performed using Bladed, a commercial software for wind turbine analysis. The length of simulation for the analysis of the dynamic response of the six degrees of freedom (DoF) motion of the floater platform under a specific load case was 3600 s. The simulation results are presented in terms of the time domain, frequency domain, and using statistical analysis. As a result of applying the resonance avoidance control algorithm, when the exclusion zone range was ±0.5 rpm from the resonance rpm, the overall performance of the wind turbine was negatively affected, and when the range was sufficiently wide at ±1 rpm, the mean power was reduced by 0.04%, and the damage equivalent load of the tower base side–side bending moment was reduced by 14.02%. The tower resonance problem of the FOWT caused by practical limitations in design and cost issues can be resolved by changing the torque control algorithm.

Coupled Dynamic Analysis for Multi-Unit Floating Offshore Wind Turbine in Maximum Operational and Survival Conditions

2015 ◽  
Author(s):  
H. K. Jang ◽  
H. C. Kim ◽  
M. H. Kim ◽  
K. H. Kim
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Time Domain ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Random Waves ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbine ◽  
Coupled Dynamic Analysis ◽  
Floating Offshore Wind Turbines

Numerical tools for a single floating offshore wind turbine (FOWT) have been developed by a number of researchers, while the investigation of multi-unit floating offshore wind turbines (MUFOWT) has rarely been performed. Recently, a numerical simulator was developed by TAMU to analyze the coupled dynamics of MUFOWT including multi-rotor-floater-mooring coupled effects. In the present study, the behavior of MUFOWT in time domain is described through the comparison of two load cases in maximum operational and survival conditions. A semi-submersible floater with four 2MW wind turbines, moored by eight mooring lines is selected as an example. The combination of irregular random waves, steady currents and dynamic turbulent winds are applied as environmental loads. As a result, the global motion and kinetic responses of the system are assessed in time domain. Kane’s dynamic theory is employed to formulate the global coupled dynamic equation of the whole system. The coupling terms are carefully considered to address the interactions among multiple turbines. This newly developed tool will be helpful in the future to evaluate the performance of MUFOWT under diverse environmental scenarios. In the present study, the aerodynamic interactions among multiple turbines including wake/array effect are not considered due to the complexity and uncertainty.

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