Searched for: author:"Özdemir, H."
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Koirala, B.P. (author), Hers, J.S. (author), Melese, Y. (author), Morales España, G.A. (author), Ozdemir, H. (author), Sijm, J.P.M. (author), Weeda, M. (author)
conference paper 2021
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Koodly Ravishankara, A. (author), Özdemir, H. (author), van der Weide, E. (author)
The surface of wind turbine blades are prone to degradation due to exposure to the elements. Rain, hail, insects are among the many causes of turbine blade degradation or erosion. Surface degradation of the wind turbine blades leads to a reduction in the aerodynamic performance, resulting in power losses. The effect of surface degradation is...
article 2021
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Koody Ravishanara, A. (author), Ozdemir, H. (author), van der Weide, E. (author)
Wind turbine aerodynamics can be broadly classified in the high Reynolds number and low Mach number regime. Flows in this regime are generally incompressible and have large regions where they can be considered as inviscid. Thus, a great number of tools have been developed with incompressible and inviscid flow assumptions. However, as wind...
conference paper 2020
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Ozdemir, H. (author)
In this chapter the derivation of the viscous integral boundary layer equations is presented in an unsteady, two-dimensional form. Closure sets for both laminar and turbulent flow conditions together with a laminar to turbulent transition method are given. The solution methods for the inviscid region and the viscous-inviscid interaction coupling...
bookPart 2020
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Koodly Ravishankara, A. (author), Bakhmet, I. (author), Ozdemir, H. (author)
Surface degradation of the wind turbine blades lead to a reduction while on the other hand blade add-ons like, vortex generators, lead to an increase in the aerodynamic performance. Within this study, both the reduction due to leading edge roughness and the increase due to vortex generators in the aerodynamic performance are quantified...
article 2020
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Ozdemir, H. (author), Koodly Ravishankara, A. (author), Bakhmet, I. (author), Caboni, M. (author)
Innovations in leading edge protective wraps or protective coatings are currently being developed to counter the effects of leading edge erosion and damage on wind turbine blades. Concurrently, the design and development of vortex generators (VGs) is taking place to counter aerodynamic stall and enhance the aerodynamic performance of wind...
report 2020
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Koodly Ravishankara, A. (author), Bakhmet, I. (author), Ozdemir, H. (author)
conference paper 2020
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Ravishanara, A.K. (author), Ozdemir, H. (author), Franco, A. (author)
In this study a new approach to model the effect of vortex generators in integral boundary layer equations is described. Vortex generators (VGs) are commonly used on wind turbine blades to avoid early separation of flow which helps not only to increase the lift but also delays the stall. Delaying the stall angle of wind turbine blades will allow...
conference paper 2019
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Vaithiyanathasamy, R. (author), Ozdemir, H. (author), Bedon, G. (author), van Garel, A. (author)
In this study a double wake model is presented for an interacting boundary layer method. The model is described initially by employing only to the inviscid flow equations and compared to the aerodynamic design tools that are including the viscous modelling (XFOIL/RFOIL) as well as to the CFD method (SU2) and experimental data on selected...
conference paper 2018
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Peeringa, J.M. (author), Ozdemir, H. (author), Kanev, S.K. (author), Shipurkar, U. (author), Baldacino, D. (author), Gunes, Y. (author), Energieonderzoek Centrum Nederland (author)
Design for Reliable Power Performance (D4REL) is an R&D project aiming at developing innovative technology & tools for reducing uncertainty in both the design and operation of offshore wind farms, with the goal of achieving substantial reduction of 6.4% of the cost of energy (CoE). <p> This project aims to develop...
report 2017
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Ozdemir, H. (author), van Garrel, A. (author), Koodly Ravishankara, A. (author), Passalacqua, F. (author), Seubers, H.J. (author), Energieonderzoek Centrum Nederland (author)
Within this study an unsteady, two-dimensional interacting boundary layer method is presented for the incompressible flow around wind turbine rotor blade sections. The main approach is to divide the flow field in to two regions; the one in the vicinity of the surface where the viscosity is e effective (so called boundary layer) and the one away...
conference paper 2017
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Ozdemir, H. (author), Ramanujam, G. (author), Energieonderzoek Centrum Nederland (author)
An improved formulation for lift estimation for integral boundary layer (IBL) methods (i.e. RFOIL, XFOIL) for thick airfoils is presented. Lift over-prediction (5 - 10% around (l=d)max) in RFOIL (similarly in XFOIL) is observed for thick airfoils for a wide range of angles of attack. The lift slope is over-predicted resulting in the increasing...
conference paper 2017
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Ozdemir, H. (author), Ramanujam, G. (author), Hoeijmakers, H.W.M. (author), Energieonderzoek Centrum Nederland (author)
An improved formulation of drag estimation for thick airfoils is presented. Drag under-prediction in XFOIL like viscous-inviscid interaction methods can be quite significant for thick airfoils used in wind turbine applications (up to 30% as seen in the present study). The improved drag formulation predicts the drag accurately for airfoils with...
conference paper 2016
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Brand, A.J. (author), Ozdemir, H. (author), Versteeg, M.C. (author)
nvt
public lecture 2013
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Ozdemir, H. (author)
n.v.t.
public lecture 2013
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Brand, A.J. (author), Ozdemir, H. (author), Versteeg, M.C. (author), Energieonderzoek Centrum Nederland (author)
Wind turbines extract energy from the flow field so that the flow in the wake of a wind turbine contains less energy and more turbulence than the undisturbed flow, leading to less energy extraction for the downstream turbines. In large wind farms, most turbines are located in the wake of one or more turbines causing the flow characteristics felt...
conference paper 2013
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Brand, A.J. (author), Bot, E.T.G. (author), Ozdemir, H. (author), Energieonderzoek Centrum Nederland (author)
The ability is demonstrated to calculate wind farm wakes on the basis of ambient conditions that were calculated with an atmospheric model. Specifically, comparisons are described between predicted and observed ambient conditions, and between power predictions from three wind farm wake models and power measurements, for a single and a double...
conference paper 2013
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Ozdemir, H. (author), Energieonderzoek Centrum Nederland (author)
conference paper 2011
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Ozdemir, H. (author)
n.v.t.
public lecture 2011
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Ozdemir, H. (author), van den Boogaard, E.F. (author), Energieonderzoek Centrum Nederland (author)
In this study the two-dimensional, unsteady integral boundary layer equations are solved numerically together with a closure set for laminar and turbulent flows. A high-order discontinuous Galerkin method is used for the spatial discretization and a multi-stage Runge-Kutta scheme is employed for the time integration. Numerical results show good...
conference paper 2011
Searched for: author:"Özdemir, H."
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