scholarly journals Effect of Upstream Side Flow of Wind Turbine on Aerodynamic Noise: Simulation Using Open-Loop Vibration in the Rod in Rod-Airfoil Configuration

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1170
Author(s):  
Mohammad Souri ◽  
Farshad Moradi Kashkooli ◽  
Madjid Soltani ◽  
Kaamran Raahemifar
Keyword(s):  
Wind Turbine ◽  
Flow Simulation ◽  
Leading Edge ◽  
Vertical Axis ◽  
Open Loop ◽  
Aerodynamic Noise ◽  
Navier Stokes ◽  
Maximum Displacement ◽  
Assessment Frequency ◽  
Side Flow

Adaptive and flexible control techniques have recently been examined as methods of controlling flow and reducing the potential noise in vertical axis wind turbines. Two-Dimensional (2D) fluid flow simulation around rod-airfoil is addressed in this study as a simple component of the wind turbine by using Unsteady Reynolds Averaged Navier–Stokes (URANS) equations for prediction of noise using Ffowcs Williams-Hawkings (FW-H) analogy. To control the flow and reduce noise, the active controlling vibration rod method is utilized with a maximum displacement ranging from 0.01 C to 1 C (C: airfoil chord). Acoustic assessment indicates that the leading edge of the blade produces noise, that by applying vibration in cylinder, blade noise in 0.1 C and 1 C decreases by 22 dB and 35 dB, respectively. Applying vibration is aerodynamically helpful since it reduces the fluctuations in the airfoil lift force by approximately 48% and those in the rod by about 46%. Strouhal assessment (frequency) shows that application of control is accompanied by 20% increase. Applying vibration in the rod reduces the flow fluctuations around the blade, thus reduces the wind turbine blade noise. This idea, as a simple example, can be used to study the incoming flow to turbines and their blades that are affected by the upstream flow.

scholarly journals Aeroacoustics behavioral study of Savonius wind turbine

2021 ◽  
Vol 2128 (1) ◽  
pp. 012033
Author(s):  
Maymouna Malainine ◽  
Amany Khaled ◽  
Sameh M Shabaan
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Sound Level ◽  
Aerodynamic Noise ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Residential Areas ◽  
Vertical Axis Wind Turbines ◽  
Computational Fluid Dynamics Cfd ◽  
Savonius Wind Turbine

Abstract Vertical Axis Wind Turbines (VAWTs) are appropriate for use in populated areas. If VAWTs were installed at residential areas, the generated aerodynamic noise can be harmful in a way or another. Therefore, in the present study, the aero-acoustics of the conventional Savonius Wind turbine was investigated using Computational Fluid Dynamics (CFD). Both the Unsteady Reynolds-averaged Navier-Stokes (URANS) equations and impermeable Ffowcs Wiliams and Hawkings (FW-H) equation were simultaneously solved. The effect of speed ratio was also studied. The results indicate that; the pressure is inversely proportional to the speed ratio. Additionally, the velocity has been increased due to the increase of the tip speed ratio. Finally, it has improved that for the majority of receivers, the overall sound level increases with increasing speed ratio.

Aerodynamic Analysis of an Airfoil With Leading Edge Pitting Erosion

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Yan Wang ◽  
Ruifeng Hu ◽  
Xiaojing Zheng
Keyword(s):  
Wind Turbine ◽  
Indirect Effects ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Distribution Area ◽  
Navier Stokes Equation ◽  
Turbine Performance ◽  
Wind Turbine Airfoil ◽  
Cfd Method

Leading edge erosion is a considerable threat to wind turbine performance and blade maintenance, and it is very imperative to accurately predict the influence of various degrees of erosion on wind turbine performance. In the present study, an attempt to investigate the effects of leading edge erosion on the aerodynamics of wind turbine airfoil is undertaken by using computational fluid dynamics (CFD) method. A new pitting erosion model is proposed and semicircle cavities were used to represent the erosion pits in the simulation. Two-dimensional incompressible Reynolds-averaged Navier–Stokes equation and shear stress transport (SST) k–ω turbulence model are adopted to compute the aerodynamics of a S809 airfoil with leading edge pitting erosions, where the influences of pits depth, densities, distribution area, and locations are considered. The results indicate that pitting erosion has remarkably undesirable influences on the aerodynamic performance of the airfoil, and the critical pits depth, density, and distribution area degrade the airfoil aerodynamic performance mostly were obtained. In addition, the dominant parameters are determined by the correlation coefficient path analysis method, results showed that all parameters have non-negligible effects on the aerodynamics of S809 airfoil, and the Reynolds number is of the most important, followed by pits density, pits depth, and pits distribution area. Meanwhile, the direct and indirect effects of these factors are analyzed, and it is found that the indirect effects are very small and the parameters can be considered to be independent with each other.

Turbulent Flow Simulation of a Runner for Francis Hydraulic Turbines Using Pseudo-Compressibility

1996 ◽  
Vol 118 (2) ◽  
pp. 285-291 ◽  
Author(s):  
Chuichi Arakawa ◽  
Yi Qian ◽  
Takashi Kubota
Keyword(s):  
Compressible Flows ◽  
Incompressible Flows ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Leading Edge ◽  
Design Tool ◽  
Design Flow ◽  
Navier Stokes ◽  
Small Computer ◽  
Strong Vortex

A three-dimensional Navier-Stokes code with pseudo-compressibility, an implicit formulation of finite difference, and a k – ε two-equation turbulence model has been developed for the Francis hydraulic runner. The viscous flow in the rotating field can be simulated well in the design flow operating condition as well as in the off-design conditions in which a strong vortex occurs due to the separation near the leading edge. Because the code employs an implicit algorithm and a wall function near the wall, it does not require a large CPU time. It can therefore be used on a small computer such as the desk-top workstation, and is available for use as a design tool. The same kind of algorithm that is used for compressible flows has been found to be appropriate for the simulation of complex incompressible flows in the field of turbomachinery.

Location of aerodynamic noise sources from a 200 kW vertical-axis wind turbine

2017 ◽  
Vol 400 ◽  
pp. 154-166 ◽  
Author(s):  
Fredric Ottermo ◽  
Erik Möllerström ◽  
Anders Nordborg ◽  
Jonny Hylander ◽  
Hans Bernhoff
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Noise ◽  
Vertical Axis Wind Turbine ◽  
Noise Sources

Prediction of Aerodynamic Noise Radiated From a Vertical-Axis Wind Turbine

2003 ◽  
Author(s):  
Akiyoshi Iida ◽  
Akisato Mizuno ◽  
Kyoji Kamemoto
Keyword(s):  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Sound Source ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Aerodynamic Noise ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Unsteady flow field and flow induced noise of vertical axis wind turbine are numerically investigated. The flow field is numerically calculated by the vortex method with core-spreading model. This simulation obtains aerodynamic performance and aerodynamic forces. Aerodynamic noise is also simulated by using Ffowcs Williams-Hawkings equation with compact body and low-Mach number assumptions. Tip speed of rotor blades are not so high, then the contribution of the moving sound source is smaller than that of the dipole sound source. Since the maximum power coefficient of VAWT can be obtained at lower tip-speed ratio compared to the conventional, horizontal axis wind turbines, the aerodynamic noise from vertical axis wind turbine is smaller than that of the conventional wind turbines at the same aerodynamic performance. This result indicates that the vertical axis wind turbines are useful to develop low-noise wind turbines.

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