A5076315831- Fluid Dynamics and Vibration Analysis
- Wind Energy Research and Development
- Wave and Wind Energy Systems
- Wind and Air Flow Studies
- Vibration and Dynamic Analysis
- Structural Health Monitoring Techniques
- Ship Hydrodynamics and Maneuverability
- Aeroelasticity and Vibration Control
- Coastal and Marine Dynamics
- Probabilistic and Robust Engineering Design
- Offshore Engineering and Technologies
- Icing and De-icing Technologies
- Aerodynamics and Fluid Dynamics Research
- Structural Integrity and Reliability Analysis
- Remote Sensing and LiDAR Applications
- Computational Fluid Dynamics and Aerodynamics
- Composite Structure Analysis and Optimization
- Lattice Boltzmann Simulation Studies
- Oil and Gas Production Techniques
- Fluid Dynamics and Turbulent Flows
- Tropical and Extratropical Cyclones Research
- Shape Memory Alloy Transformations
- Fluid Dynamics Simulations and Interactions
- Aerospace Engineering and Energy Systems
- Engineering Applied Research
National Technical University of Athens
2012-2022
National Taiwan University of Arts
2016
University of Patras
1995
Offshore wind turbines are designed and analyzed using comprehensive simulation tools (or codes) that account for the coupled dynamics of inflow, aerodynamics, elasticity, controls turbine, along with incident waves, sea current, hydrodynamics, mooring dynamics, foundation support structure. This paper describes latest findings code-to-code verification activities Code Comparison Collaboration Continuation project, which operates under International Energy Agency Wind Task 30. In phase...
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...
The present paper deals with the development of a multi-purpose floating tension leg platform (TLP) concept suitable for combined offshore wind and wave energy resources exploitation, taking into account prevailing environmental conditions at selected locations along European coastline. examined Renewable Energy Multi-Purpose Floating Offshore System (REFOS) encompasses an array hydrodynamically interacting oscillating water column (OWC) devices, moored through tensioned tethers as TLP...
This paper summarizes the coupled hydro-aero-elastic analysis of a multi-purpose floating structure suitable for offshore wind and wave energy exploitation. The incorporates properly solutions diffraction pressure- motion- dependent radiation problems around aerodynamics 5 MW Wind Turbine (WT). Finite water depths are considered, being under action regular surface waves. platform encompasses three hydrodynamically interacting Oscillating Water Column (OWC) devices consisting concentric...
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...
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...
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...
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...
In the paper, potential to alleviate wind turbine loads through combined implementation of different passive and active control methods is assessed. Passive accomplished blade designs with build in material and/or geometric bend-twist coupling (BTC). The first materialized by introducing an offset angle on plies uni-directional over spar caps blade, while latter sweeping elastic axis respect pitch axis. Active considered individual (IPC) or concurrent use flap (IPC+IFC). Different...
Abstract The paper addresses Vortex Induced Vibrations (VIV) caused by tower vortex shedding through LES simulations of a wind tunnel experiment. A high-fidelity (HiFi), Fluid Structure Interaction (FSI) framework for aeroelastic analysis 3D flexible cylinders is established, based on the open-source Computational Dynamics (CFD) code OpenFOAM and coupling library preCICE. In present study, FSI employed with aim to replicate low Reynolds (Re=26000) forced vibrations experiment circular...
Abstract Solvers based on Boundary Element Method (BEM) are fast and they have proven to provide accurate results in a wide range of applications. On the other hand, computational fluid dynamics (CFD) solvers high-fidelity tools able account for viscous effects. However, computationally demanding. In present work, limitations BEM exploited considering case study moonpool type floater which effects near sharp edges body (vortex shedding) not negligible. The compared with from an unsteady...
This paper presents the coupled analysis performed in frequency and time domain, considering a multi-purpose floating structure suitable for offshore wind wave energy source exploitation. The encompasses an array of hydrodynamically interacting Oscillating Water Column (OWC) devices, moored through tensioned tethers as Tension Leg Platform (TLP), supports 10 MW Wind Turbine (WT). is built to incorporate properly solutions diffraction pressure- motion-dependent radiation problems around...
In the paper, an individual flap control (IFC) algorithm based on wind speed measurements obtained with a spinner anemometer is presented. The controller uses actuators aim to remove any deterministic source of load variation blades, associated asymmetries inflow. Such variations are concentrated multiples rotational frequency (p multiples) and they mainly due yaw, inclination atmospheric boundary layer (ABL) shear. assist operation conventional feed-back pitch (IPC) thereby reduce its duty...
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. considers: a) aerodynamic effects caused power...
The possibility of alleviating wind turbine loads through blade trailing edge shape morphing is investigated in the present paper. Emphasis put on analyzing effect flap geometry load reduction levels. choice deformation camber line as well chordwise and spanwise dimensions are addressed. analysis concerns conceptual DTU 10 MW RWT. Aeroelastic control materialized a standard individual controller. Furthermore, comb ined pitch-flap controller evaluated found to advantages compared only...