Searched for: author%3A%22Pereira%2C+R%22
(1 - 13 of 13)
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Mazza, P. (author), Balbino dos Santos Pereira, R. (author), De Oliveira, G. (author)
This work presents an airfoil probabilistic design methodology for wind energy applications, using an analytical approach to estimate the angle-of-attack fluctuations produced by non-uniformities in the incoming wind field. The contemplated wind speed perturbations include wind shear, yaw misalignment and atmospheric turbulence, and several...
journal article 2020
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Wade, Bryce (author), Balbino dos Santos Pereira, R. (author), Wade, Cameron (author)
Offshore wind energy is emerging as a large contributor to installed renewable energy capacity. In order to continue the momentum of its development, the offshore wind industry is looking to continually lower the levelized cost of electricity (LCOE). One area being explored in an effort to lower the LCOE of offshore wind generation is the...
journal article 2019
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De Oliveira Andrade, G.L. (author), Balbino dos Santos Pereira, R. (author), Timmer, W.A. (author), van Rooij, R.P.J.O.M. (author)
The accuracy of airfoil polar predictions is limited by the usage of imperfect turbulence models. Can machine-learning improve this situation? Will airfoil polars teach the effect of turbulence on skin-friction? We try to answer these questions by refining turbulence treatment in the Rfoil code: boundary layer closure relations are learned...
journal article 2018
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Balbino dos Santos Pereira, R. (author), De Oliveira Andrade, G.L. (author), Timmer, W.A. (author), Quaeghebeur, Erik (author)
We describe a probabilistic approach to design airfoils for wind energy applications. An analytical expression is derived for the probability of perturbations to the operational blade-section angle of attack. It includes the combined influence of wind shear, yaw-misalignment, and turbulence intensity. The theoretical fluctuations in angle of...
journal article 2018
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Rezaeiha, Abdolrahim (author), Balbino dos Santos Pereira, R. (author), Kotsonis, M. (author)
Unsteady loads are a major limiting factor for further upscaling of HAWTs considering the high costs associated to strict structural requirements. Alleviation of these unsteady loads on HAWT blades, e.g. using active flow control (AFC), is of high importance. In order to devise effective AFC methods, the unsteady loading sources need to be...
journal article 2017
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De Oliveira Andrade, G.L. (author), Balbino dos Santos Pereira, R. (author), van Bussel, G.J.W. (author), Avallone, F. (author), Ragni, D. (author)
Flow augmentation consists in modifying mass flow across the actuation plane of a rotor to enhance energy extraction or propulsive efficiency. The talk sketches the distinction between passive and active rotor augmentation strategies. Power coefficient trends are compared analytically while numerical results illustrate differences in flow...
abstract 2017
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Staring, M. (author), Pereira, R (author), Douma, H (author), van der Neut, J.R. (author), Wapenaar, C.P.A. (author)
We present an adaptive double-focusing method for applying source-receiver Marchenko redatuming to field data. Receiver redatuming is achieved by a first focusing step, where the coupled Marchenko equations are iteratively solved for the oneway Green’s functions. Next, source redatuming is typically performed by a multi-dimensional deconvolution...
conference paper 2017
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Balbino dos Santos Pereira, R. (author)
The contribution of sustainable Wind Energy (WE) to the global energy scenario has been steadily increasing over the past decades. In the process, Horizontal Axis Wind Turbines (HAWT) became the most widespread and largest WE harvesting machines. Nevertheless, significant challenges still lie ahead of further expansion of HAWT, namely concerning...
doctoral thesis 2016
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De Oliveira Andrade, G.L. (author), Balbino dos Santos Pereira, R. (author), Timmer, W.A. (author), Ragni, D. (author), Lau, F. (author), van Bussel, G.J.W. (author)
There are many ways to learn from data. Our first experiment consisted in reproducing the way aerodynamicists work [2] with a genetic optimizer. The data pool was too narrow and asymptotic tendencies were unreliable. Our 2nd Experiment, a simple version of [4], had a virtually unlimited data pool and used neural networks. Results were better,...
poster 2016
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De Oliveira Andrade, G.L. (author), Balbino dos Santos Pereira, R. (author), Ragni, D. (author), Avallone, F. (author), van Bussel, G.J.W. (author)
The article seeks to unify the treatment of conservative force interactions between axi-symmetric bodies and actuators in inviscid ow. Applications include the study of hub interference, di_user augmented wind turbines and boundary layer ingestion propeller con_gurations. The conservation equations are integrated over in_nitesimal streamtubes to...
journal article 2016
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We study through high resolution numerical simulations unknown features of a random velocity field based on the so-called multiplicative chaos, previously proposed in the literature to model turbulence. We investigate the influence of the intermittency parameter, observing the behaviour of the field as it is changed. In this way, we can...
conference paper 2015
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Pereira, R. (author), Van Bussel, G.J.W. (author), Timmer, W.A. (author)
The increasing size of Horizontal Axis Wind Turbines and the trend to install wind farms further offshore demand more robust design options. If the pitch system could be eliminated, the availability of Horizontal Axis Wind Turbines should increase. This research investigates the use of active stall control to regulate power production in...
journal article 2014
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Pereira, R. (author), Schepers, G. (author), Pavel, M.D. (author)
The aim of this study is to assess the load predicting capability of a classical Beddoes-Leishman dynamic stall model in a horizontal axis wind turbine (HAWT) environment, in the presence of yaw-misalignment. The dynamic stall model was tailored to the HAWT environment, and validated against unsteady thick airfoil data. Subsequently, the dynamic...
conference paper 2011
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