scholarly journals The Array Optimization of Vertical Axis Wind Turbine Based on a New Asymmetric Wake Model

2021 ◽  
Vol 9 (8) ◽  
pp. 820
Author(s):  
Zheng Yuan ◽  
Qihu Sheng ◽  
Ke Sun ◽  
Jun Zang ◽  
Xuewei Zhang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Goal Function ◽  
Mean Amplitude ◽  
Vertical Axis ◽  
Good Choice ◽  
Vertical Axis Wind Turbine ◽  
Gaussian Functions ◽  
Array Optimization ◽  
Wake Model ◽  
Increasing Demand

With the increasing demand for wind energy, the vertical axis wind turbine (VAWT) is attracting more and more attention. In order to design the VAWT array for better performance, the VAWT wake model needs to reflect the wake characteristics well. Based on the asymmetric wake characteristic, a new VAWT wake model is proposed in this paper, which is a combination of two semi Gaussian functions with different deviations, and can be called the “double semi Gaussian functions wake model”. The model is simple and has only four parameters (mean, amplitude, left deviation and right deviation). Compared with the traditional Gaussian and Top-hat model, this model can better reflect the asymmetric characteristic of the VAWT wake. In particular, it can describe the behavior of wake merging in the case of counter-rotating twin turbines. Based on this wake model, the velocity field of VAWT array can be reproduced accurately. The goal function is mainly based on the performance of a basic array unit, and it can ensure the rapidity of the optimization process. The optimal arrangements under two different criteria are analyzed. Moreover, the truncation ratio is introduced to ensure that the downstream turbine works at the rated condition, and the optimal arrangements under different truncation ratios are analyzed. In this paper, the proposed wake model provides a good choice for the preliminary design of the VAWT array, and some relevant suggestions on the array arrangement have been put forward.

scholarly journals Theoretical Modeling of Vertical-Axis Wind Turbine Wakes

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 10 ◽  
Author(s):  
Mahdi Abkar
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Measurement Data ◽  
Vertical Axis ◽  
Theoretical Models ◽  
Momentum Balance ◽  
Vertical Axis Wind Turbine ◽  
Gaussian Shape ◽  
Velocity Defect ◽  
Wake Model

In this work, two different theoretical models for predicting the wind velocity downwind of an H-rotor vertical-axis wind turbine are presented. The first model uses mass conservation together with the momentum theory and assumes a top-hat distribution for the wind velocity deficit. The second model considers a two-dimensional Gaussian shape for the velocity defect and satisfies mass continuity and the momentum balance. Both approaches are consistent with the existing and widely-used theoretical wake models for horizontal-axis wind turbines and, thus, can be implemented in the current numerical codes utilized for optimization and real-time applications. To assess and compare the two proposed models, we use large eddy simulation as well as field measurement data of vertical-axis wind turbine wakes. The results show that, although both models are generally capable of predicting the velocity defect, the prediction from the Gaussian-based wake model is more accurate compared to the top-hat counterpart. This is mainly related to the consistency of the assumptions used in the Gaussian-based wake model with the physics of the turbulent wake development downwind of the turbine.

scholarly journals Development of a parameterized reduced-order vertical-axis wind turbine wake model

2019 ◽  
Vol 44 (5) ◽  
pp. 494-508 ◽  
Author(s):  
Eric B Tingey ◽  
Andrew Ning
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Computational Cost ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Reduced Order ◽  
Wake Interactions ◽  
Wake Model ◽  
Turbine Wake

Analyzing or optimizing wind farm layouts often requires reduced-order wake models to estimate turbine wake interactions and wind velocity. We propose a wake model for vertical-axis wind turbines in streamwise and crosswind directions. Using vorticity data from computational fluid dynamic simulations and cross-validated Gaussian distribution fitting, we produced a wake model that can estimate normalized wake velocity deficits of an isolated vertical-axis wind turbine using normalized downstream and lateral positions, tip-speed ratio, and solidity. Compared with computational fluid dynamics, taking over a day to run one simulation, our wake model predicts a velocity deficit in under a second with an appropriate accuracy and computational cost necessary for wind farm optimization. The model agreed with two experimental studies producing percent differences of the maximum wake deficit of 6.3% and 14.6%. The wake model includes multiple wake interactions and blade aerodynamics to calculate power, allowing its use in wind farm layout analysis and optimization.

Calculating the aerodynamics of vertical axis wind turbines

2012 ◽  
Vol 34 (3) ◽  
pp. 169-184 ◽  
Author(s):  
Hoang Thi Bich Ngoc
Keyword(s):  
Wind Turbine ◽  
Incidence Angle ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Velocity Triangle ◽  
Relationship Of ◽  
The Relationship

Vertical axis wind turbine technology has been applied last years, very long after horizontal axis wind turbine technology. Aerodynamic problems of vertical axis wind machines are discussible. An important problem is the determination of the incidence law in the interaction between wind and rotor blades. The focus of the work is to establish equations of the incidence depending on the blade azimuth, and to solve them. From these results, aerodynamic torques and power can be calculated. The incidence angle is a parameter of velocity triangle, and both the factors depend not only on the blade azimuth but also on the ratio of rotational speed and horizontal speed. The built computational program allows theoretically selecting the relationship of geometric parameters of wind turbine in accordance with requirements on power, wind speed and installation conditions.

Design and Analysis of Vertical Axis Wind Turbine

2017 ◽  
Author(s):  
Prof. R.K. Bhoyar ◽  
Prof. S.J. Bhadang ◽  
Prof. N.Z. Adakane ◽  
Prof. N.D. Pachkawade
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine
Sign in / Sign up

Export Citation Format

Share Document