Hydrodynamic Response of Three Column Semi-Submersible Floater Supporting Vertical Axis Wind Turbine

2017 ◽  
Author(s):  
Rajeswari Krishnan ◽  
Nallayarasu Seeninaidu
Keyword(s):  
Numerical Simulations ◽  
Wind Turbine ◽  
Wind Farms ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Scale Model ◽  
Vertical Axis Wind Turbine ◽  
Ocean Engineering ◽  
Motion Response ◽  
Wave Basin

Offshore wind energy extraction has gathered momentum around the world due to its advantages over onshore wind farms at various fronts. The floating support system with vertical axis wind turbine might prove to be feasible concept in medium to deep waters. In this context, this paper addresses an investigation of hydrodynamic analysis of three column semi-submersible with Vertical Axis Wind Turbine (VAWT) in parked condition under regular and random waves. Free decay experiments were conducted for using scale model (1:75) in a laboratory wave basin at the Department of Ocean Engineering in Indian Institute of Technology Madras, India. Computational Fluid Dynamics (CFD) simulations were used to assess damping characteristics and validated with the experiments. Numerical simulations of hydrodynamic motion response of the floater were carried out using potential flow theory based commercial software (ANSYS AQWA). The damping values obtained from experiments were used in numerical simulations to obtain motion response and Response Amplitude Operator (RAO). The motion response obtained from the study was used to verify the suitability of the system for deployment in east and west coast of India.

Mean Wave Drift Force on a Barge-Type Floating Wind Turbine With Moonpools

2021 ◽  
Author(s):  
Lei Tan ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
Koichi Masuda
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Hydrodynamic Performance ◽  
Vertical Axis Wind Turbine ◽  
Rotating Speed ◽  
Wave Drift ◽  
Floating Offshore Wind Turbines ◽  
Drift Force ◽  
Gyroscopic Effects

Abstract The barge-type foundation with moonpool(s) is a promising type of platform for floating offshore wind turbines, since the moonpool(s) could improve the hydrodynamic performance at particular frequencies and reduce the costs of construction. In this paper, the horizontal mean drift force and yaw drift moment of a barge-type platform with four moonpools are numerically and experimentally investigated. Physical model tests are carried out in a wave tank, where a 2MW vertical-axis wind turbine is modelled in the 1:100 scale. By varying the rotating speed of the turbine and the mass of the blades, the gyroscopic effects due to turbine rotations on the mean drift forces are experimentally examined. The wave diffraction and radiation code WAMIT is used to carry out numerical analysis of wave drift force and moment. The experimental results indicate that the influence of the rotations of a vertical-axis wind turbine on the sway drift force is generally not very significant. The predictions by WAMIT are in reasonable agreement with the measured data. Numerical results demonstrate that the horizontal mean drift force and yaw drift moment at certain frequencies could be reduced by moonpool(s).

Numerical Simulation for the Starting Characteristics of a Wind Turbine

2020 ◽  
Vol 38 ◽  
pp. 215-221
Author(s):  
Anna Kuwana ◽  
Xue Yan Bai ◽  
Dan Yao ◽  
Haruo Kobayashi
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farms ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Optimum Shape ◽  
Blade Thickness ◽  
Basic Characteristics ◽  
Starting Characteristics

There are many types of wind turbine. Large propeller-type wind turbines are used mainly for large wind farms and offshore wind power generation. Small vertical-axis wind turbines (VAWTs) are often used in distributed energy systems. In previous studies on wind turbines, the basic characteristics such as torque coefficient have often been obtained during rotation, with the turbine rotating at a constant speed. Such studies are necessary for the proper design of wind turbines. However, it is also necessary to conduct research under conditions in which the wind direction and wind speed change over time. Numerical simulation of the starting characteristics is carried out in this study. Based on the flow field around the wind turbine, the force required to rotate the turbine is calculated. The force used to stop the turbine is modeled based on friction in relation to the bearing. Equations for the motion of the turbine are solved by their use as external force. Wind turbine operation from the stationary state to the start of rotation is simulated. Five parameters, namely, blade length, wind turbine radius, overlap, gap, and blade thickness, are changed and the optimum shape is obtained. The simulation results tend to qualitatively agree with the experimental results for steadily rotating wind turbines in terms of two aspects: (1) the optimal shape has an 20% overlap of the turbine radius, and (2) the larger the gap, the lower the efficiency.

scholarly journals On mooring line tension and fatigue prediction for offshore vertical axis wind turbines: A comparison of lumped mass and quasi-static approaches

2018 ◽  
Vol 42 (2) ◽  
pp. 97-107 ◽  
Author(s):  
D Cevasco ◽  
M Collu ◽  
CM Rizzo ◽  
M Hall
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Line Tension ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Mooring Line ◽  
Offshore Wind Turbine ◽  
Vertical Axis Wind Turbine ◽  
Lumped Mass ◽  
Vertical Axis Wind Turbines

Despite several potential advantages, relatively few studies and design support tools have been developed for floating vertical axis wind turbines. Due to the substantial aerodynamics differences, the analyses of vertical axis wind turbine on floating structures cannot be easily extended from what have been already done for horizontal axis wind turbines. Therefore, the main aim of the present work is to compare the dynamic response of the floating offshore wind turbine system adopting two different mooring dynamics approaches. Two versions of the in-house aero-hydro-mooring coupled model of dynamics for floating vertical axis wind turbine (FloVAWT) have been used, employing a mooring quasi-static model, which solves the equations using an energetic approach, and a modified version of floating vertical axis wind turbine, which instead couples with the lumped mass mooring line model MoorDyn. The results, in terms of mooring line tension, fatigue and response in frequency have been obtained and analysed, based on a 5 MW Darrieus type rotor supported by the OC4-DeepCwind semisubmersible.

Two-Dimensional Computational Fluid Dynamics Study on the Performance of Twin Vertical Axis Wind Turbine With Deflector

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Yichen Jiang ◽  
Peidong Zhao ◽  
Li Zou ◽  
Zhi Zong ◽  
Kun Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Energy Utilization ◽  
Offshore Wind ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Local Flow

Abstract The offshore wind industry is undergoing a rapid development due to its advantage over the onshore wind farm. The vertical axis wind turbine (VAWT) is deemed to be potential in offshore wind energy utilization. A design of the offshore vertical axis wind turbine with a deflector is proposed and studied in this paper. Two-dimensional computational fluid dynamics (CFD) simulation is employed to investigate the aerodynamic performance of wind turbine. An effective method of obtaining the blade’s angle of attack (AoA) is introduced in CFD simulation to help analyze the blade aerodynamic torque variation. The numerical simulations are validated against the measured torque and wake velocity, and the results show a good agreement with the experiment. It is found that the blade instantaneous torque is correlated with the local AoA. Among the three deflector configurations, the front deflector leads to favorable local flow for the blade, which is responsible for the improved performance.

Physical Model Testing of the TetraSpar Demo Floating Wind Turbine Prototype

2019 ◽  
Author(s):  
Michael Borg ◽  
Anthony Viselli ◽  
Christopher K. Allen ◽  
Matthew Fowler ◽  
Christoffer Sigshøj ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Numerical Models ◽  
Model Testing ◽  
Offshore Wind ◽  
Scale Model ◽  
Test Facility ◽  
Hydrodynamic Characteristics ◽  
Ocean Engineering ◽  
Floating Wind Turbine ◽  
Floating Offshore Wind Turbines

Abstract As part of the process of deploying new floating offshore wind turbines, scale model testing is carried out to de-risk and verify the design of novel foundation concepts. This paper describes the testing of a 1:43 Froude-scaled model of the TetraSpar Demo floating wind turbine prototype that shall be installed at the Metcentre test facility, Norway. The TetraSpar floating foundation concept consists of a floater tetrahedral structure comprising of braces connected together through pinned connections, and a triangular keel structure suspended below the floater by six suspension lines. A description of the experimental setup and program at the Alfond W2 Ocean Engineering Lab at University of Maine is given. The objective of the test campaign was to validate the initial design, and contribute to the development of the final demonstrator design and numerical models. The nonlinear hydrodynamic characteristics of the design are illustrated experimentally and the keel suspension system is shown to satisfy design criteria.

scholarly journals Aerodynamic Design of a Small-Scale Model of a Vertical Axis Wind Turbine

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1465 ◽  
Author(s):  
Andrés Meana-Fernández ◽  
Jesús Manuel Fernández Oro ◽  
Katia María Argüelles Díaz ◽  
Mónica Galdo-Vega ◽  
Sandra Velarde-Suárez
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Scale Model ◽  
Small Scale ◽  
Wind Tunnel Testing ◽  
Aerodynamic Design ◽  
Vertical Axis Wind Turbine ◽  
Small Scale Model ◽  
Tunnel Testing

Wind tunnel testing of small-scale models is one of the most useful techniques to predict the performance of real-scale applications. In this work, the aerodynamic design and the construction of a small-scale model of a straight-bladed vertical axis wind turbine for wind tunnel testing has been performed. Using a double multiple streamtube model (DMST), different solidity values for the turbine and different airfoil geometries were compared to select the final design. Once an optimal design was selected, a numerical simulation using Computational Fluid Dynamics (CFD) was performed in order to obtain a more precise description of the flow field as well as the performance of the model. Future work will comprise the characterization of the model and the comparison of the experimental and numerical results.

scholarly journals Design and 3D CFD Static Performance Study of a Two-Blade IceWind Turbine

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5356
Author(s):  
Hamdy Mansour ◽  
Rola Afify
Keyword(s):  
Wind Turbine ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Scale Model ◽  
Vertical Axis Wind Turbine ◽  
Performance Study ◽  
Static Performance ◽  
New Type ◽  
Torque Values ◽  
Static Torque

The IceWind turbine, a new type of Vertical Axis Wind Turbine, was proposed by an Iceland based startup. It is a product that has been featured in few published scientific research studies. This paper investigates the IceWind turbine’s performance numerically. Three-dimensional numerical simulations are conducted for the full scale model using the SST K-ω model at a wind speed of 15.8 m/s. The following results are documented: static torque, velocity distributions and streamlines, and pressure distribution. Comparisons with previous data are established. Additionally, comparisons with the Savonius wind turbine in the same swept area are conducted to determine how efficient the new type of turbine is. The IceWind turbine shows a similar level of performance with slightly higher static torque values. Vortices behind the IceWind turbine are confirmed to be three-dimensional and are larger than those of Savonius turbine.

Experimental Testing of a Wind Tunnel Model for Use in a Vertical Axis Wind Turbine

2010 ◽  
Author(s):  
Chad C. Panther ◽  
Kenny A. Williams ◽  
Jay P. Wilhelm ◽  
James E. Smith
Keyword(s):  
Wind Tunnel ◽  
Rapid Prototyping ◽  
Wind Turbine ◽  
Model Building ◽  
Experimental Testing ◽  
Vertical Axis ◽  
Scale Model ◽  
Circulation Control ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge

Experimental testing was performed on a circulation controlled airfoil with upper and lower trailing edge blowing slots, controlled by span wise pneumatic valves. The augmented blade was designed for application to a circulation controlled vertical axis wind turbine. The design is based upon a conventional NACA0018 shape, replacing the sharp trailing edge with a rounded Coanda surface and blowing slots. A scale model with a chord of 8 inches and span of 16.5 inches was created using an ABS plastic rapid prototyping machine. In the past, circulation control wind tunnel models have been constructed with a separate blowing slot and trailing edge using conventional machining methods. The slot must be tediously aligned along the span for a consistent height which ultimately affects the uniformity and performance of the circulation control jet in combination with the flow rate. The rapid prototyping machine eased fabrication as a modular trailing edge section was printed which includes the Coanda surface, blowing slot, and diffuser all in one piece. Pressure taps were integrated by the prototyping machine into both the printed skin and trailing edge module. This method left additional space inside the model for circulation control valving components and eliminated the need for machining pressure ports. This paper will outline the model building procedures, wind tunnel test rig, and experimental results. Aerodynamic forces were determined by both load cells and surface pressure measurements; the agreement between the two methods will be analyzed and addressed. Test conditions include various angles of attack (±20°) at Cμ = 0, 0.02, 0.06, and 0.10; the test Reynolds number was kept constant at 300K. The results indicate that the blade performed at ΔCl/Cμ near 30 for Cμ = 0.02.

Design and Aero-Elastic Simulation of a 5MW Floating Vertical Axis Wind Turbine

2012 ◽  
Author(s):  
Luca Vita ◽  
Uwe S. Paulsen ◽  
Helge A. Madsen ◽  
Per H. Nielsen ◽  
Petter A. Berthelsen ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Waves ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
The European Union ◽  
Vertical Axis Wind Turbine ◽  
Floating Platform ◽  
Mooring Lines ◽  
Sea Bed

This paper deals with the design of a 5MW floating offshore Vertical Axis Wind Turbine (VAWT). The design is based on a new offshore wind turbine concept (DeepWind concept), consisting of a Darrieus rotor mounted on a spar buoy support structure, which is anchored to the sea bed with mooring lines [1]. The design is carried out in an iterative process, involving the different sub-components and addressing several conflicting constraints. The present design does not aim to be the final optimum solution for this concept. Instead, the goal is to have a baseline model, based on the present technology, which can be improved in the future with new dedicated technological solutions. The rotor uses curved blades, which are designed in order to minimize the gravitational loads and to be produced by the pultrusion process. The floating platform is a slender cylindrical structure rotating along with the rotor, whose stability is achieved by adding ballast at the bottom. The platform is connected to the mooring lines with some rigid arms, which are necessary to absorb the torque transmitted by the rotor. The aero-elastic simulations are carried out with Hawc2, a numerical solver developed at Risø-DTU. The numerical simulations take into account the fully coupled aerodynamic and hydrodynamic loads on the structure, due to wind, waves and currents. The turbine is tested in operative conditions, at different sea states, selected according to the international offshore standards. The research is part of the European project DeepWind (2010–2014), which has been financed by the European Union (FP7-Future Emerging Technologies).

scholarly journals EXPERIMENTAL STUDY ON THE LOADING AND SCOUR OF THE JACKET TYPE OFFSHORE WIND TURBINE FOUNDATION

2011 ◽  
Vol 1 (32) ◽  
pp. 25
Author(s):  
Ray-Yeng Yang ◽  
Hsin-Hung Chen ◽  
Hwung-Hweng Hwung ◽  
Wen-Pin Jiang ◽  
Nian-Tzu Wu
Keyword(s):  
Wind Turbine ◽  
Water Depth ◽  
Fixed Bed ◽  
Offshore Wind ◽  
Scale Model ◽  
Offshore Wind Turbine ◽  
Wave Flume ◽  
Wave Basin ◽  
Scour Protection ◽  
The Impact

A 1:36 scale model tests were carried out in the Medium Wave Flume (MWF) and Near-shore Wave Basin (NSWB) at the Tainan Hydraulics Laboratory (THL) with the jacket type offshore wind turbine foundation located in the test area. The loading of typhoon wave with current on the jacket type offshore wind turbine foundation was investigated in the MWF with fixed bed experiment. Meanwhile, the scour around the jacket type offshore wind turbine foundation exposed to wave and current was conducted in the NSWB with the moveable bed experiment. Two locations (water depth 12m and 16m) of the foundations are separately simulated in this study. Based on the analysis from the former NSWB experimental results, the suitable scour protection of a four-layer work around the foundation is also proposed to the impact of scour. Finally, a four-layer scour protection is tested and found to be effective in preventing scour around jacket type foundation of offshore wind turbines at water depth 12m and 16m.

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