A5052439426- Wind and Air Flow Studies
- Wind Energy Research and Development
- Fluid Dynamics and Vibration Analysis
- Aerodynamics and Acoustics in Jet Flows
- Aerodynamics and Fluid Dynamics Research
- Computational Fluid Dynamics and Aerodynamics
- Fluid Dynamics and Turbulent Flows
- Icing and De-icing Technologies
- Acoustic Wave Phenomena Research
- Meteorological Phenomena and Simulations
- Fluid Dynamics Simulations and Interactions
- Wind Turbine Control Systems
- Noise Effects and Management
- Underwater Acoustics Research
- Vehicle Noise and Vibration Control
- Energy Load and Power Forecasting
- Hungarian Social, Economic and Educational Studies
- Structural Analysis of Composite Materials
- Aerospace and Aviation Technology
- Aeolian processes and effects
- Remote Sensing and LiDAR Applications
- Aerospace Engineering and Energy Systems
- Structural Health Monitoring Techniques
- Lattice Boltzmann Simulation Studies
- Biomimetic flight and propulsion mechanisms
National Technical University of Athens
2005-2023
Center for Renewable Energy Sources and Saving
2007-2015
United States Department of Energy
2011
ABSTRACT Computational fluid dynamic (CFD) methods are used in this paper to predict the power production from entire wind farms complex terrain and shed some light into wake flow patterns. Two full three‐dimensional Navier–Stokes solvers for incompressible flow, employing k − ϵ ω turbulence closures, used. The turbines modeled as momentum absorbers by means of their thrust coefficient through actuator disk approach. Alternative estimating reference speed calculation tested. work presented...
The paper presents research conducted in the Flow workpackage of EU funded UPWIND project which focuses on improving models flow within and downwind large wind farms complex terrain offshore. main activity is modelling behaviour turbine wakes order to improve power output predictions.
Abstract The modelling of wind turbine wakes is investigated in this paper using a Navier–Stokes solver employing the k–ω turbulence model appropriately modified for atmospheric flows. It common knowledge that even single‐wind wake predictions with computational fluid dynamic methods underestimate near deficit, directly contributing to overestimation power downstream turbines. For turbine, alternative enhancements under neutral and stable conditions are tested account eventually correct...
ABSTRACT This paper describes an analysis of wake measurements from the research farm at ECN Wind Turbine Test Site Wieringermeer. is owned and operated by Energy Research Centre Netherlands. The consists five turbines that are oriented in a single line with mutual distance 3.8D(iameter). variable speed pitch controlled, they have diameter hub height 80 m. rated power 2.5 MW. Extensive machine (power, loads, yaw angle angles) carried out on these turbines. In parallel, meteorological done...
The concept of a large (~20MW) multi-rotor wind turbine intended for offshore installations is analysed with respect to its aerodynamic performance. effect closely clustering rotors on single actuator disk estimated using two different modelling approaches: CFD solver in which the are simulated as distinct disks and vortex based blade geometry exactly considered. In present work, system 7 centre spacing 1.05D. At nominal conditions (tip speed ratio=9) both models predict an increase power...
SCADA data, recorded on the downstream wind farm, has been used to identify flow cases with visible clustering effects. The inflow condition is derived from a partly undisturbed turbine, due lack of mast measurements. data analysis concludes that centre deficit for farm disturbed distinct maximum zone located only 5-10D entrance. This zone, representing 20-30% speed reduction, increases and moves increasing cluster effect not outside sector 20-30°. eight models represented in this benchmark...
The IEA Task 31 Wakebench is setting up a framework for the evaluation of wind farm flow models operating at microscale level.The consists on model protocol integrated web-based portal benchmarking (www.windbench.net).This paper provides an overview building-block validation approach applied to flow-over-terrain models, including best practices and data processing procedures analysis qualification datasets from resource assessment campaigns.A hierarchy test cases has been proposed...
Abstract Various propagation models have been developed to estimate the level of noise near residential areas. Predictions and measurements proven that proper modelling medium is particular importance. In present work, calculations are performed using a ray theory methodology. The trajectory transport equations derived from linear acoustics for moving in three dimensions. Ground atmospheric absorption, wave refraction diffraction turbulence taken into account by introducing appropriate...
Practical aspects concerning the use of 3D Navier-Stokes solvers as prediction tools for micro-siting wind energy installations are considered. Micro-siting is an important issue a successful application in sites complex terrain. There constantly increasing interest using mean flow predictions based on Reynolds averaged (RANS) order to minimize number required field measurements. In this connection, certain numerical aspects, such extent domain, choice appropriate inflow boundary conditions,...
In this paper, the accuracy of an in-house Actuator Line (AL) model is tested on aeroelastic simulations a Wind Turbine (WT) rotor and helicopter Main Rotor (MR) under uniform free-stream flow. For scope analyses, AL coupled with multibody dynamics code in which blades are modeled as beams. The advantage from introduction CFD analysis rotorcraft aeroelasticity related to its capability account detail for interaction wake boundary layer developed surrounding bodies. This has proven be great...
Abstract Recent research developments have indicated that substantial reduction of both the fatigue and ultimate loads can be achieved by adopting trailing edge (TE) flap control strategies. Their aeroelastic tools employ blade element momentum (BEM) aerodynamic models enhanced with a sectional 2D treatment TE flap, neglecting 3D effect trailed vorticity in vicinity moving flap. In present paper, cross comparison BEM‐based used analysis against higher fidelity, free‐wake lifting line, fully...
The present paper focuses on wind turbine rotor modeling for loads and wake flow prediction. Two steady-state models based the actuator disk approach are considered, using either a uniform thrust or blade element momentum calculation of loads. A third model is unsteady-state line approach. Predictions compared with measurements in tunnel experiments atmospheric environment capabilities weaknesses different addressed.
The FP7 AdVanced Aerodynamic Tools for lArge Rotors - Avatar project aims to develop and validate advanced aerodynamic models, be used in integral design codes the next generation of large scale wind turbines (10-20MW). One approaches towards reaching rotors 10-20MW size is application flow control devices, such as flaps. In Task 3.2: Development modelling devices on aerofoils and, project, are benchmarked validated against experimental data a DU95W180 airfoil steady unsteady flow, different...
Flapping-foil thrusters are systems that operate at a substantially lower frequency compared with marine propellers and characterized by much smaller power concentration. These biomimetic devices able to very efficiently, offering desirable levels of thrust required for the propulsion small vessels or autonomous underwater vehicles (AUVs), can be used standalone augmenting ship in waves, alleviating generation noise its adverse effects on sea life, particularly mammals. In this work, we...
The prediction of noise emitted from operating wind turbines is important to planners in order avoid the possibility surpassing allowable limits close residential areas. To this end, wave equation solved, taking into account atmospheric and ground characteristics that affect sound propagation. In present paper, a ray tracing methodology capable performing axisymmetric calculations field around an isolated source used. simulates all main physical mechanisms influence propagation performs for...
Morphing offers an attractive alternative compared to conventional hinged, multi-element high lift devices. In the present work, morphed shapes of a NACA 64A010 airfoil are optimized for maximum characteristics. Deformed leading and trailing edge represented through Bezier curves derived from locally defined control points. The optimization process employs fast Foil2w in-house viscous-inviscid interaction solver calculation aerodynamic Transitional flow results indicate that combined...