Comparative Study of the Inline Configuration Wind Farm

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Alaa S. Hasan ◽  
Tarek Elgammal ◽  
Randall S. Jackson ◽  
Ryoichi S. Amano
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Stokes Equations ◽  
Experimental Testing ◽  
Wind Tunnel Test ◽  
Body Motion ◽  
Computational Domain ◽  
Horizontal Axis Wind Turbine ◽  
Depth Analysis

Abstract This research provides an in-depth analysis of the flow around the rotor and in the wake of a single horizontal axis wind turbine (HAWT) model at different free stream velocities and tip speed ratios (TSRs). Moreover, it extracts some recommendations that might be beneficial for large-scale projects such as wind farm layout design and power output prediction. For this purpose, modeling and experimental testing of a wind tunnel test section, including a single wind turbine model inside were created and validated against present experimental data of the same model. The large Eddy simulation (LES) was used as a numerical approach to model the Navier–Stokes equations. The computational domain was divided into two areas: rotational and stationary. The unsteady rigid body motion (RBM) model was adopted to represent the rotor rotation accurately.

scholarly journals Recent Advances in Wind Turbine Noise Research

Acoustics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 171-206 ◽  
Author(s):  
Colin Hansen ◽  
Kristy Hansen
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Research Work ◽  
Wind Farms ◽  
Horizontal Axis ◽  
Future Research ◽  
Noise Generation ◽  
Horizontal Axis Wind Turbine ◽  
Wind Turbine Noise

This review is focussed on large-scale, horizontal-axis upwind turbines. Vertical-axis turbines are not considered here as they are not sufficiently efficient to be deployed in the commercial generation of electricity. Recent developments in horizontal-axis wind turbine noise research are summarised and topics that are pertinent to the problem, but are yet to be investigated, are explored and suggestions for future research are offered. The major portion of recent and current research on wind turbine noise generation, propagation and its effects on people and animals is being undertaken by groups in Europe, UK, USA, Japan, Australia and New Zealand. Considerable progress has been made in understanding wind turbine noise generation and propagation as well as the effect of wind farm noise on people, birds and animals. However, much remains to be done to answer many of the questions for which answers are still uncertain. In addition to community concerns about the effect of wind farm noise on people and how best to regulate wind farm noise and check installed wind farms for compliance, there is considerable interest from turbine manufacturers in developing quieter rotors, with the intention of allowing wind farm installations to be closer to populated areas. The purpose of this paper is to summarise recent and current wind farm noise research work and the research questions that remain to be addressed or are in the process of being addressed. Topics that are the subject of on-going research are discussed briefly and references to recent and current work are included.

Overview of Subsynchronous Oscillation in Grid-connected Wind Farm

2020 ◽  
Vol 13 (7) ◽  
pp. 969-979
Author(s):  
Xu Pei-Zhen ◽  
Lu Yong-Geng ◽  
Cao Xi-Min
Keyword(s):  
Power Systems ◽  
Wind Turbine ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Induction Generator ◽  
Future Research ◽  
Stable Operation ◽  
Subsynchronous Oscillation ◽  
Different Types

Background: Over the past few years, the subsynchronous oscillation (SSO) caused by the grid-connected wind farm had a bad influence on the stable operation of the system and has now become a bottleneck factor restricting the efficient utilization of wind power. How to mitigate and suppress the phenomenon of SSO of wind farms has become the focus of power system research. Methods: This paper first analyzes the SSO of different types of wind turbines, including squirrelcage induction generator based wind turbine (SCIG-WT), permanent magnet synchronous generator- based wind turbine (PMSG-WT), and doubly-fed induction generator based wind turbine (DFIG-WT). Then, the mechanisms of different types of SSO are proposed with the aim to better understand SSO in large-scale wind integrated power systems, and the main analytical methods suitable for studying the SSO of wind farms are summarized. Results: On the basis of results, using additional damping control suppression methods to solve SSO caused by the flexible power transmission devices and the wind turbine converter is recommended. Conclusion: The current development direction of the SSO of large-scale wind farm grid-connected systems is summarized and the current challenges and recommendations for future research and development are discussed.

Small Horizontal Axis Wind Turbine: Analytical Blade Design and Comparison With RANS-Prediction and First Experimental Data

2013 ◽  
Author(s):  
Tom Gerhard ◽  
Michael Sturm ◽  
Thomas H. Carolus
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Wind Turbine ◽  
Horizontal Axis ◽  
Analytical Models ◽  
Power Coefficient ◽  
Analysis Tool ◽  
Computational Domain ◽  
Horizontal Axis Wind Turbine ◽  
Data Set

State-of-the-art wind turbine performance prediction is mainly based on semi-analytical models, incorporating blade element momentum (BEM) analysis and empirical models. Full numerical simulation methods can yield the performance of a wind turbine without empirical assumptions. Inherent difficulties are the large computational domain required to capture all effects of the unbounded ambient flow field and the fact that the boundary layer on the blade may be transitional. A modified turbine design method in terms of the velocity triangles, Euler’s turbine equation and BEM is developed. Lift and drag coefficients are obtained from XFOIL, an open source 2D design and analysis tool for subcritical airfoils. A 3 m diameter horizontal axis wind turbine rotor was designed and manufactured. The flow field is predicted by means of a Reynolds-averaged Navier-Stokes simulation. Two turbulence models were utilized: (i) a standard k-ω-SST model, (ii) a laminar/turbulent transition model. The manufactured turbine is placed on the rooftop of the University of Siegen. Three wind anemometers and wind direction sensors are arranged around the turbine. The torque is derived from electric power and the rotational speed via a calibrated grid-connected generator. The agreement between the analytically and CFD-predicted kinematic quantities up- and downstream of the rotor disc is quite satisfactory. However, the blade section drag to lift ratio and hence the power coefficient vary with the turbulence model chosen. Moreover, the experimentally determined power coefficient is considerably lower as predicted by all methods. However, this conclusion is somewhat preliminary since the existing experimental data set needs to be extended.

scholarly journals CFD Simulation and Experimental Study on Coupled Motion Response of Ship with Tank in Beam Waves

2022 ◽  
Vol 10 (1) ◽  
pp. 113
Author(s):  
Tao He ◽  
Dakui Feng ◽  
Liwei Liu ◽  
Xianzhou Wang ◽  
Hua Jiang
Keyword(s):  
Working Conditions ◽  
Large Scale ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Body Motion ◽  
Time Step ◽  
Coupled Motion ◽  
Motion Response ◽  
Time Step Size ◽  
Tank Sloshing

Tank sloshing is widely present in many engineering fields, especially in the field of marine. Due to the trend of large-scale liquid cargo ships, it is of great significance to study the coupled motion response of ships with tanks in beam waves. In this study, the CFD (Computational Fluid Dynamics) method and experiments are used to study the response of a ship with/without a tank in beam waves. All the computations are performed by an in-house CFD solver, which is used to solve RANS (Reynold Average Navier-Stokes) equations coupled with six degrees-of-freedom solid-body motion equations. The Level Set Method is used to solve the free surface. Verification work on the grid number and time step size has been conducted. The simulation results agree with the experimental results well, which shows that the numerical method is accurate enough. In this paper, several different working conditions are set up, and the effects of the liquid height in the tank, the size of the tank and the wavelength ratio of the incident wave on the ship’s motion are studied. The results show the effect of tank sloshing on the ship’s motion in different working conditions.

Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning

2011 ◽  
Author(s):  
M. Sergio Campobasso ◽  
Mohammad H. Baba-Ahmadi
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Harmonic Balance ◽  
Stokes Equations ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Computational Performance

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time- and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.

Effect of wind turbine nacelle on turbine wake dynamics in large wind farms

2019 ◽  
Vol 869 ◽  
pp. 1-26 ◽  
Author(s):  
Daniel Foti ◽  
Xiaolei Yang ◽  
Lian Shen ◽  
Fotis Sotiropoulos
Keyword(s):  
Wind Turbine ◽  
Coherent Structures ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Practical Significance ◽  
Mean Velocity ◽  
Velocity Deficit ◽  
Farm Scale ◽  
Turbine Wake

Wake meandering, a phenomenon of large-scale lateral oscillation of the wake, has significant effects on the velocity deficit and turbulence intensities in wind turbine wakes. Previous studies of a single turbine (Kang et al., J. Fluid. Mech., vol. 774, 2014, pp. 374–403; Foti et al., Phys. Rev. Fluids, vol. 1 (4), 2016, 044407) have shown that the turbine nacelle induces large-scale coherent structures in the near field that can have a significant effect on wake meandering. However, whether nacelle-induced coherent structures at the turbine scale impact the emergent turbine wake dynamics at the wind farm scale is still an open question of both fundamental and practical significance. We take on this question by carrying out large-eddy simulation of atmospheric turbulent flow over the Horns Rev wind farm using actuator surface parameterisations of the turbines without and with the turbine nacelle taken into account. While the computed mean turbine power output and the mean velocity field away from the nacelle wake are similar for both cases, considerable differences are found in the turbine power fluctuations and turbulence intensities. Furthermore, wake meandering amplitude and area defined by wake meanders, which indicates the turbine wake unsteadiness, are larger for the simulations with the turbine nacelle. The wake influenced area computed from the velocity deficit profiles, which describes the spanwise extent of the turbine wakes, and the spanwise growth rate, on the other hand, are smaller for some rows in the simulation with the nacelle model. Our work shows that incorporating the nacelle model in wind farm scale simulations is critical for accurate predictions of quantities that affect the wind farm levelised cost of energy, such as the dynamics of wake meandering and the dynamic loads on downwind turbines.

Parametric Stiffness in Large-Scale Wind-Turbine Blades and the Effects on Resonance and Speed Locking

2020 ◽  
Author(s):  
Ayse Sapmaz ◽  
Brian F. Feeny
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Turbine Blades ◽  
Relative Strength ◽  
Wind Turbine Blades ◽  
Fixed Position ◽  
Horizontal Axis Wind Turbine ◽  
Parametric Effect ◽  
Parametric Effects ◽  
Blade Tip

Abstract This paper is on parametric effect in large scale horizontal-axis wind-turbine blades and speed locking phenomenon for a simplified model of the in-plane blade-hub dynamics. The relative strength of the parametric stiffness is evaluated for actual and scaled-length blades. Fixed-position natural frequencies are found at different rotation angles to show the significance of the gravity’s parametric effect. The ratio of the parametric and elastic modal stiffness is then estimated for the scaled versions of the NREL’s blades for four models to present the relation between the blade size and the parametric effects. The parametric effect on blade tip placements are investigated for superharmonic resonances at orders two and three for blades of various lengths. An analysis of speed-locking is presented, and interpreted for the various blades.

scholarly journals Impact of Economic Indicators on the Integrated Design of Wind Turbine Systems

2018 ◽  
Vol 8 (9) ◽  
pp. 1668 ◽  
Author(s):  
Jianghai Wu ◽  
Tongguang Wang ◽  
Long Wang ◽  
Ning Zhao
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Production ◽  
Large Scale ◽  
Wind Farm ◽  
Net Present Value ◽  
Integrated Design ◽  
Aerodynamic Performance ◽  
System Level ◽  
Blade Length

This article presents a framework to integrate and optimize the design of large-scale wind turbines. Annual energy production, load analysis, the structural design of components and the wind farm operation model are coupled to perform a system-level nonlinear optimization. As well as the commonly used design objective levelized cost of energy (LCoE), key metrics of engineering economics such as net present value (NPV), internal rate of return (IRR) and the discounted payback time (DPT) are calculated and used as design objectives, respectively. The results show that IRR and DPT have the same effect as LCoE since they all lead to minimization of the ratio of the capital expenditure to the energy production. Meanwhile, the optimization for NPV tends to maximize the margin between incomes and costs. These two types of economic metrics provide the minimal blade length and maximal blade length of an optimal blade for a target wind turbine at a given wind farm. The turbine properties with respect to the blade length and tower height are also examined. The blade obtained with economic optimization objectives has a much larger relative thickness and smaller chord distributions than that obtained for high aerodynamic performance design. Furthermore, the use of cost control objectives in optimization is crucial in improving the economic efficiency of wind turbines and sacrificing some aerodynamic performance can bring significant reductions in design loads and turbine costs.

scholarly journals Wind Turbine Wake Modeling in Accelerating Wind Field: A Preliminary Study on a Two-Dimensional Hill

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 153 ◽  
Author(s):  
Omar M. A. M. Ibrahim ◽  
Shigeo Yoshida ◽  
Masahiro Hamasaki ◽  
Ao Takada
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Field ◽  
Complex Terrain ◽  
Wind Farm ◽  
Wind Tunnel Test ◽  
Two Dimensional ◽  
Preliminary Study ◽  
Wake Model

Complex terrain can influence wind turbine wakes and wind speed profiles in a wind farm. Consequently, predicting the performance of wind turbines and energy production over complex terrain is more difficult than it is over flat terrain. In this preliminary study, an engineering wake model, that considers acceleration on a two-dimensional hill, was developed based on the momentum theory. The model consists of the wake width and wake wind speed. The equation to calculate the rotor thrust, which is calculated by the wake wind speed profiles, was also formulated. Then, a wind-tunnel test was performed in simple flow conditions in order to investigate wake development over a two-dimensional hill. After this the wake model was compared with the wind-tunnel test, and the results obtained by using the new wake model were close to the wind-tunnel test results. Using the new wake model, it was possible to estimate the wake shrinkage in an accelerating two-dimensional wind field.

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