A5003850252- Wind Energy Research and Development
- Fluid Dynamics and Vibration Analysis
- Wind and Air Flow Studies
- Aerodynamics and Fluid Dynamics Research
- Computational Fluid Dynamics and Aerodynamics
- Vibration and Dynamic Analysis
- Fluid Dynamics and Turbulent Flows
- Aerospace and Aviation Technology
- Structural Health Monitoring Techniques
- Wave and Wind Energy Systems
- Aerospace Engineering and Energy Systems
- Aeroelasticity and Vibration Control
- Icing and De-icing Technologies
- Lattice Boltzmann Simulation Studies
- Shape Memory Alloy Transformations
- Fluid Dynamics Simulations and Interactions
- Advanced Aircraft Design and Technologies
- Modeling and Simulation Systems
- Simulation Techniques and Applications
- Real-time simulation and control systems
- Modeling, Simulation, and Optimization
- Dynamics and Control of Mechanical Systems
- Biomimetic flight and propulsion mechanisms
- Aerodynamics and Acoustics in Jet Flows
- Probabilistic and Robust Engineering Design
National Technical University of Athens
2016-2025
Italian Aerospace Research Centre
2024
University of Stuttgart
2024
Office National d'Études et de Recherches Aérospatiales
2024
China Aerodynamics Research and Development Center
2024
Huazhong University of Science and Technology
2016
National Taiwan University of Arts
2016
National and Kapodistrian University of Athens
2008
ABSTRACT There seems to be a significant uncertainty in aerodynamic and aeroelastic simulations on megawatt turbines operating inflow with considerable shear, particular the engineering blade element momentum (BEM) model, commonly implemented design codes used by industry. Computations advanced vortex computational fluid dynamics models are provide improved insight into complex flow phenomena rotor aerodynamics caused sheared inflow. One consistent result from is variation of induced...
As the size of commercial wind turbines increases, new blade designs become more flexible in order to comply with requirement for reduced weights. In normal operation conditions, blades undergo large bending deflections, which exceed 10% their radius, while significant torsion angles toward tip are obtained, potentially affect performance and stability. present paper, effects on loads a turbine from structural nonlinearities induced by deflections assessed, based simulations carried out NREL...
Abstract Aeroelastic stability is a key issue in the design process of wind turbines towards both enchanced and increased fatigue life. The theory models behind state‐of‐the‐art aeroelastic tools developed for analysis complete turbine at Centre Renewable Energy Sources National Technical University Athens are presented this article. Application examples calculations pitch, variable speed stall‐regulated also presented. Copyright © 2004 John Wiley & Sons, Ltd.
Abstract. This paper presents the integration of a near-wake model for trailing vorticity, which is based on prescribed-wake lifting-line proposed by Beddoes(1987), with blade element momentum (BEM)-based far-wake and 2-D shed vorticity model. The resulting coupled aerodynamics validated against lifting-surface computations performed using free-wake panel code. focus description numerical stability, computation speed accuracy unsteady simulations. To stabilize model, it has to be iterated...
Abstract. In this work, the vortex-induced vibration (VIV) phenomenon affecting a wind turbine airfoil section at 90° incidence is analysed with two numerical approaches, two-dimensional (2D) setup of airfoil, simulated using unsteady Reynolds-averaged Navier–Stokes equations, and three-dimensional (3D) span-to-chord aspect ratio 1, employing delayed detached-eddy simulation model. A constant inflow velocity considered for Reynolds number around 2×106. The only structural degree freedom...
Abstract. This paper presents a feasibility analysis of vertical wake steering for floating turbines by differential ballast control. new concept is based on the idea pitching floater with respect to water surface, thereby achieving desired tilt turbine rotor disk. The pitch attitude controlled moving among columns floater. study considers application control conceptual 10 MW wind installed two platforms, differing in size, weight, and geometry. following: (a) aerodynamic effects caused...
The influence of interactional effects on quadrotor performance in forward flight was evaluated taking into account square and diamond configurations, backward tilt angles, a range hub spacings including overlapping blades. analysis based the wind-tunnel measurements simulations from four midfidelity computational methods high-fidelity tool. outcome indicates that efficiency configuration improves by 5% comparison with isolated rotors for nonoverlapping rotor spacings, while interactions...
Abstract The prediction of the aerodynamic performance pitching airfoils in stall conditions is considered context strong viscous–inviscid interaction modelling. aim work to demonstrate capabilities a low‐cost dynamic model well suited for engineering applications. formulated on basis standard panel method combined with vortex blob approximation wake. development boundary layer over airfoil and evolution shear wake are taken into account by means coupling. To this end transpiration added...
In the course of AVATAR project, partner predictions for key load components in storm/idle conditions separated two groups. One group showed large loading due to edgewise instability, other damped oscillation and lower levels. To identify cause this separation, impact structural aerodynamic modeling options on damping stall-induced vibrations is investigated simplified operating a single blade. The choice dynamic stall model found be primary driver, therefore most likely also reason...
A fully coupled hydro-servo-aero-elastic simulator for the analysis of floating offshore wind turbines (FOWTs) is presented. All physical aspects are addressed, and corresponding equations concurrently solved within same computational framework, taking into account wave excitations, aerodynamic response rotor, hydrodynamic floater, structural dynamics turbine-floater-mooring lines assembly finally control system turbine. The components complex multi-physics a FOWT interact with each other in...
Abstract Modern wind turbines are prone to Vortex Induced Vibrations (VIV). In the present work, an engineering semi-empirical framework is proposed that assesses VIV aero-elastic instabilities of turbine configurations. The procedure employs tools relying on airfoil polars. It uses state-of-the-art tool hGAST along with EUROCODE for steel structures extended provides missing modal input data (i.e. frequencies, total structural plus aerodynamic damping and modeshapes) evaluate...
Vortex-induced and stall-induced vibrations of a 2D elastically mounted airfoil at high angles attack in the vicinity 90° are investigated using vortex type model. Such conditions encountered parked or idling operation extreme yaw provoked by control system failures. At very attack, massive flow separation takes place over entire blade span, shedding evolves downstream giving rise to periodically varying loads frequencies corresponding Strouhal number vortices shed wake. As result,...
Abstract The study presents and compares aerodynamic simulations for an airfoil section with adaptive trailing edge flap, which deflects following a smooth deformation shape. are carried out three substantially different methods: Reynolds‐averaged Navier–Stokes solver, viscous–inviscid interaction method engineering dynamic stall model suitable implementation in aeroelastic codes based on blade element momentum theory. integral forces pitching moment coefficients first determined steady...
Abstract. Wind turbine rotors in idling operation mode can experience high angles of attack within the post-stall region that are capable triggering stall-induced vibrations. The aim present paper is to extend existing knowledge on dynamics and aerodynamics an wind characterize its stability. Rotor stability slow assessed basis nonlinear time domain linear eigenvalue analyses. establish when analysis reliable identify cases for which effects significant. Analysis performed a 10 MW conceptual...
Abstract Upscaling of wind turbine blades calls for implementation innovative active load control concepts that will facilitate the flawless operation machine and reduce fatigue ultimate loads hinder its service life. Based on aeroelastic simulations prove enhanced capabilities combined individual pitch flap at global scale level, a shape adaptive concept encompasses an articulated mechanism consisting two subparts is presented. Shape memory alloy (SMA) actuators are investigated assessed as...
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...