Effects of root Gurney flaps on the aerodynamic performance of a horizontal axis wind turbine
TL;DR: In this article, the effects of Gurney flaps on the aerodynamic performance of a horizontal axis wind turbine, which is part of the EU FP7 AVATAR project, were investigated.
About: This article is published in Energy.The article was published on 2019-11-15. It has received 29 citations till now. The article focuses on the topics: Gurney flap & Turbine.
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Journal Article•
TL;DR: Comparisons of experimental results and complimentary computations for airfoils with vortex generators are compared and indicate that with appropriate calibration, engineering-type tools can capture the effects of vortex generators and outperform more complex tools.
Abstract: Experimental results and complimentary computations for airfoils with vortex generators are compared in this paper, as part of an e_ort within the AVATAR project to develop tools for wind turbine blade control devices. Measurements from two airfoils equipped with passive vortex generators, a 30% thick DU97W300 and an 18% thick NTUA T18 have been used for benchmarking several simulation tools. These tools span low-to-high complexity, ranging from engineering-level integral boundary layer tools to fully-resolved computational uid dynamics codes. Results indicate that with appropriate calibration, engineering-type tools can capture the e_ects of vortex generators and outperform more complex tools. Fully resolved CFD comes at a much higher computational cost and does not necessarily capture the increased lift due to the VGs. However, in lieu of the limited experimental data available for calibration, high _delity tools are still required for assessing the e_ect of vortex generators on airfoil performance.
32 citations
TL;DR: This review performs a comprehensive and up-to-date literature survey of selected flow-control devices, from their time of development up to the present, along with a comparative analysis centered on their aerodynamic controllability.
Abstract: It is projected that, in the following years, the wind-energy industry will maintain its rapid growth over the last few decades. Such growth in the industry has been accompanied by the desirability and demand for larger wind turbines aimed at harnessing more power. However, the fact that massive turbine blades inherently experience increased fatigue and ultimate loads is no secret, which compromise their structural lifecycle. Accordingly, this demands higher overhaul-and-maintenance (O&M) costs, leading to higher cost of energy (COE). Introduction of flow-control devices on the wind turbine is a plausible solution to this issue. Flow-control mechanisms feature the ability to effectively enhance/suppress turbulence, advance/delay flow transition, and prevent/promote separation, leading to enhancement in aerodynamic and aeroacoustics performance, load alleviation and fluctuation suppression, and eventually wind turbine power augmentation. These flow-control devices are operated primarily under two schemes: passive and active control. Development and optimization of flow-control devices present the potential for reduction in the COE, which is a major challenge against traditional power sources. This review performs a comprehensive and up-to-date literature survey of selected flow-control devices, from their time of development up to the present. It contains a discussion on the current prospects and challenges faced by these devices, along with a comparative analysis centered on their aerodynamic controllability. General considerations and conclusive remarks are presented after the discussion.
23 citations
TL;DR: In this paper, the effects of jet blowing on blade suction side of NREL phase VI horizontal axis wind turbine (HAWT ) for alleviation of degraded flow due to boundary layer separation were investigated.
15 citations
TL;DR: A comprehensive review on numerical approaches of wind turbine blade analysis using CFD is done in this article , where the turbine's structural integrity can be investigated using Finite Element Structural Analysis or a Fluid Structural Interaction Study.
7 citations
TL;DR: In this article , a new bionic method is proposed to improve the wind energy utilization of wind turbine on the premise of strictly controlling the aerodynamic noise and load level of blade, which can provide a reference for the optimization of energy efficiency and noise research of NREL phase VI HAWT.
6 citations
References
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TL;DR: In this article, a general, numerical, marching procedure is presented for the calculation of the transport processes in three-dimensional flows characterised by the presence of one coordinate in which physical influences are exerted in only one direction.
5,946 citations
Book•
01 Feb 1986
TL;DR: In this article, Navier-Stokes et al. discuss the fundamental principles of Inviscid, Incompressible Flow over airfoils and their application in nonlinear Supersonic Flow.
Abstract: TABLE OF CONTENTS Preface to the Fifth Edition Part 1: Fundamental Principles 1. Aerodynamics: Some Introductory Thoughts 2. Aerodynamics: Some Fundamental Principles and Equations Part 2: Inviscid, Incompressible Flow 3. Fundamentals of Inviscid, Incompressible Flow 4. Incompressible Flow Over Airfoils 5. Incompressible Flow Over Finite Wings 6. Three-Dimensional Incompressible Flow Part 3: Inviscid, Compressible Flow 7. Compressible Flow: Some Preliminary Aspects 8. Normal Shock Waves and Related Topics 9. Oblique Shock and Expansion Waves 10. Compressible Flow Through Nozzles, Diffusers and Wind Tunnels 11. Subsonic Compressible Flow Over Airfoils: Linear Theory 12. Linearized Supersonic Flow 13. Introduction to Numerical Techniques for Nonlinear Supersonic Flow 14. Elements of Hypersonic Flow Part 4: Viscous Flow 15. Introduction to the Fundamental Principles and Equations of Viscous Flow 16. A Special Case: Couette Flow 17. Introduction to Boundary Layers 18. Laminar Boundary Layers 19. Turbulent Boundary Layers 20. Navier-Stokes Solutions: Some Examples Appendix A: Isentropic Flow Properties Appendix B: Normal Shock Properties Appendix C: Prandtl-Meyer Function and Mach Angle Appendix D: Standard Atmosphere Bibliography Index
3,113 citations
01 Oct 1992
TL;DR: In this article, two new versions of the k-omega two-equation turbulence model are presented, the baseline model and the Shear-Stress Transport model, which is based on the BSL model, but has the additional ability to account for the transport of the principal shear stress in adverse pressure gradient boundary layers.
Abstract: Two new versions of the k-omega two-equation turbulence model will be presented. The new Baseline (BSL) model is designed to give results similar to those of the original k-omega model of Wilcox, but without its strong dependency on arbitrary freestream values. The BSL model is identical to the Wilcox model in the inner 50 percent of the boundary-layer but changes gradually to the high Reynolds number Jones-Launder k-epsilon model (in a k-omega formulation) towards the boundary-layer edge. The new model is also virtually identical to the Jones-Lauder model for free shear layers. The second version of the model is called Shear-Stress Transport (SST) model. It is based on the BSL model, but has the additional ability to account for the transport of the principal shear stress in adverse pressure gradient boundary-layers. The model is based on Bradshaw's assumption that the principal shear stress is proportional to the turbulent kinetic energy, which is introduced into the definition of the eddy-viscosity. Both models are tested for a large number of different flowfields. The results of the BSL model are similar to those of the original k-omega model, but without the undesirable freestream dependency. The predictions of the SST model are also independent of the freestream values and show excellent agreement with experimental data for adverse pressure gradient boundary-layer flows.
1,709 citations
TL;DR: In this article, the authors defined the upper surface lift coefficient of an airfoil chord and defined the freestream conditions at the leading edge of the chord line, and the ratio of specific heats.
Abstract: Nomenclature c = airfoil chord CL = lift coefficient = L/!/2pV00c CLu = upper-surface lift coefficient Cp = pressure coefficient = (p -p^)/ Ap Vx 2 Mx = freestream Mach number p = static pressure Re^ = freestream Reynolds number based on airfoil chord = V^clv sp = location of leading-edge stagnation point V^ — freestream velocity v local velocity on airfoil surface x = distance along chord line F = circulation about the airfoil 7 = ratio of specific heats v = kinematic viscosity p = density () oo = freestream conditions () t e = conditions at the airfoil trailing edge
522 citations
TL;DR: A review of the state of the art and present status of active aeroelastic rotor control research for wind turbines is presented in this paper, where the authors discuss the potential of load reduction using smart rotor control concepts.
491 citations