A Viscous Three-Dimensional Differential/Actuator-Disk Method for the Aerodynamic Analysis of Wind Farms

2002 ◽  
Vol 124 (4) ◽  
pp. 345-356 ◽  
Author(s):  
Idriss Ammara ◽  
Christophe Leclerc ◽  
Christian Masson
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Stokes Equations ◽  
Control Volume ◽  
Three Dimensional ◽  
Wind Farms ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Promising Tool ◽  
Strip Theory

Computational Fluid Dynamics (CFD) is a promising tool for the analysis and optimization of wind turbine positioning inside wind parks (also known as wind farms) in order to maximize power production. In this paper, 3-D, time-averaged, steady-state, incompressible Navier-Stokes equations, in which wind turbines are represented by surficial forces, are solved using a Control-Volume Finite Element Method (CVFEM). The fundamentals of developing a practical 3-D method are discussed in this paper, with an emphasis on some of the challenges that arose during their implementation. For isolated turbines, results have indicated that the proposed 3-D method attains the same level of accuracy, in terms of performance predictions, as the previously developed 2-D axisymmetric method and the well-known momentum-strip theory. Furthermore, the capability of the proposed method to predict wind turbine wake characteristics is also illustrated. Satisfactory agreement with experimental measurements has been achieved. The analysis of a two-row periodic wind farm in neutral atmospheric boundary layers demonstrate the existence of positive interference effects (venturi effects) as well as the dominant influence of mutual interference on the performance of dense wind turbine clusters.

scholarly journals Effect of Impeller Parameters on the Flow inside the Centrifugal Blower using CFD

2020 ◽  
Vol 8 (6) ◽  
pp. 3977-3980
Keyword(s):  
Numerical Analysis ◽  
Stokes Equations ◽  
Control Volume ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Computational Domain ◽  
Centrifugal Blower ◽  
Impeller Blade ◽  
Navier Stokes Equations

A numerical analysis is carried out to understand the flow characteristics for different impeller configurations of a single stage centrifugal blower. The volute design is based on constant velocity method. Four different impeller configurations are selected for the analysis. Impeller blade geometry is created with point by point method. Numerical simulation is carried out by CFD software GAMBIT 2.4.6 and FLUENT 6.3.26. GAMBIT work includes geometry definition and grid generation of computational domain. This process includes selection of grid types, grid refinements and defining correct boundary conditions. Processing work is carried out in FLUENT. The viscous Navier-Stokes equations are solved with control volume approach and the k-ε turbulence model. In this three dimensional numerical analysis is carried out with steady flow approach. The rotor and stator interaction is solved by mixing plane approach. Results of simulation are presented in terms of flow parameters, at impeller outlet and various angular positions inside the volute. Also, the contours of flow properties are presented at the outlet plane of fluid domain. Results suggest that for the same configurations of centrifugal blower, as we change geometrical parameter of impeller the flow inside the blower get affected.

scholarly journals Wind Farm Fault Detection by Monitoring Wind Speed in the Wake Region

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6559
Author(s):  
Minh-Quang Tran ◽  
Yi-Chen Li ◽  
Chen-Yang Lan ◽  
Meng-Kun Liu
Keyword(s):  
Energy Dissipation ◽  
Wind Speed ◽  
Fault Detection ◽  
Wind Turbine ◽  
Wind Farm ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Wake Region ◽  
Navier Stokes Equations ◽  
Dissipation Model

A novel concept of wind farm fault detection by monitoring the wind speed in the wake region is proposed in this study. A wind energy dissipation model was coupled with a computational fluid dynamics solver to simulate the fluid field of a wind turbine array, and the wind velocity and direction in the simulation were exported for identifying wind turbine faults. The 3D steady Navier–Stokes equations were solved by using the cell center finite volume method with a second order upwind scheme and a k−ε turbulence model. In addition, the wind energy dissipation model, derived from energy balance and Betz’s law, was added to the Navier–Stokes equations’ source term. The simulation results indicate that the wind speed distribution in the wake region contains significant information regarding multiple wind turbine faults. A feature selection algorithm specifically designed for the analysis of wind flow was proposed to reduce the number of features. This algorithm proved to have better performance than fuzzy entropy measures and recursive feature elimination methods under a limited number of features. As a result, faults in the wind turbine array could be detected and identified by machine learning algorithms.

scholarly journals An Aerodynamic Method for the Analysis of Isolated Horizontal-Axis Wind Turbines

1997 ◽  
Vol 3 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Christian Masson ◽  
Idriss Ammara ◽  
Ion Paraschivoiu
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Stokes Equations ◽  
Control Volume ◽  
Wind Farms ◽  
Horizontal Axis ◽  
Research Activities ◽  
Performance Predictions ◽  
Strip Theory ◽  
Horizontal Axis Wind Turbines

The aerodynamic analysis of a wind turbine represents a very complex task since it involves an unsteady three-dimensional viscous flow. In most existing performance-analysis methods, wind turbines are considered isolated so that interference effects caused by other rotors or by the site topology are neglected. Studying these effects in order to optimize the arrangement and the positioning of Horizontal-Axis Wind Turbines (HAWTs) on a wind farm is one of the research activities of the Bombardier Aeronautical Chair. As a preliminary step in the progress of this project, a method that includes some of the essential ingredients for the analysis of wind farms has been developed and is presented in the paper. In this proposed method, the flow field around isolated HAWTs is predicted by solving the steady-state, incompressible, two-dimensional axisymmetric Navier-Stokes equations. The turbine is represented by a distribution of momentum sources. The resulting governing equations are solved using a Control-Volume Finite Element Method (CVFEM). This axisymmetric implementation efficiently illustrates the applicability and viability of the proposed methodology, by using a formulation that necessitates a minimum of computer resources. The axisymmetric method produces performance predictions for isolated machines with the same level of accuracy than the well-known momentum-strip theory. It can therefore be considered to be a useful tool for the design of HAWTs. Its main advantage, however, is its capacity to predict the flow in the wake which constitutes one of the essential features needed for the performance predictions of wind farms of dense cluster arrangements.

Effect of temperature-dependency of Newtonian and non-Newtonian fluid properties on the dynamics of droplet impinging on hot surfaces

2015 ◽  
Vol 26 (09) ◽  
pp. 1550106 ◽  
Author(s):  
A. R. Binesh ◽  
S. M. Mousavi ◽  
R. Kamali
Keyword(s):  
Stokes Equations ◽  
Control Volume ◽  
Three Dimensional ◽  
Effect Of Temperature ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Droplet Dynamics ◽  
Computational Fluid Dynamics Analysis ◽  
Fluid Properties ◽  
Hot Surface

In the present work, three-dimensional computational fluid dynamics analysis is employed to study the droplet dynamics of Newtonian and non-Newtonian droplets impinging on a hot surface under various impact conditions. The Navier–Stokes equations for unsteady, incompressible, and viscous fluid flow are solved using a control volume method. The volume-of-fluid (VOF) technique is also used to track the free-surface of the liquid. The effect of viscosity, density and surface tension on droplet dynamics is evaluated considering their dependence of temperature. The results indicate that the temperature dependence of the both Newtonian and non-Newtonian physicochemical liquid properties must be considered to obtain better agreement of the numerical results with experimental data. After ensuring the accuracy of the numerical methodology, the internal behavior of the droplets is examined, which is shown that the receding velocity of the non-Newtonian droplet is slower than the Newtonian one.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

The inlet flow structure of a conceptual open-nose supersonic drone

2021 ◽  
pp. 095441002098304
Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun
Keyword(s):  
Flow Structure ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computational Fluid Dynamic Simulation ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Aerodynamic Efficiency ◽  
Performance Effects

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

scholarly journals A Code for Simulating Heat Transfer in Turbulent Channel Flow

Mathematics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 756
Author(s):  
Federico Lluesma-Rodríguez ◽  
Francisco Álcantara-Ávila ◽  
María Jezabel Pérez-Quiles ◽  
Sergio Hoyas
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Turbulent Channel Flow ◽  
Passive Scalar ◽  
Direct Numerical Simulations ◽  
Time Dependent ◽  
Navier Stokes ◽  
Thermal Flow ◽  
Navier Stokes Equations

One numerical method was designed to solve the time-dependent, three-dimensional, incompressible Navier–Stokes equations in turbulent thermal channel flows. Its originality lies in the use of several well-known methods to discretize the problem and its parallel nature. Vorticy-Laplacian of velocity formulation has been used, so pressure has been removed from the system. Heat is modeled as a passive scalar. Any other quantity modeled as passive scalar can be very easily studied, including several of them at the same time. These methods have been successfully used for extensive direct numerical simulations of passive thermal flow for several boundary conditions.

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