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Shokoofeh Abbaszadeh

Bio: Shokoofeh Abbaszadeh is an academic researcher from Otto-von-Guericke University Magdeburg. The author has contributed to research in topics: Turbine & Turbine blade. The author has an hindex of 3, co-authored 4 publications receiving 28 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the effect of flexible structures in a highly dynamic flow regime including separation and stall is studied systematically in an experimental setup which permits observations of all regimes ranging from quasi-static state up to the occurrence of deep dynamic stall and beyond.

25 citations

Journal ArticleDOI
TL;DR: In this paper, a bioinspired approach with hyperflexible turbine blades is proposed to reduce flow separation and stall in a passive manner, which results in higher efficiency and increased turbine lifetime through decreased structural loads.
Abstract: State-of-the-art technologies for wind and tidal energy exploitation focus mostly on axial turbines. However, cross-flow hydrokinetic tidal turbines possess interesting features, such as higher area-based power density in array installations and shallow water, as well as a generally simpler design. Up to now, the highly unsteady flow conditions and cyclic blade stall have hindered deployment at large scales because of the resulting low single-turbine efficiency and fatigue failure challenges. Concepts exist which overcome these drawbacks by actively controlling the flow, at the cost of increased mechatronical complexity. Here, we propose a bioinspired approach with hyperflexible turbine blades. The rotor naturally adapts to the flow through deformation, reducing flow separation and stall in a passive manner. This results in higher efficiency and increased turbine lifetime through decreased structural loads, without compromising on the simplicity of the design.

10 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental method to obtain the motion law of a pitch system required for maximising the power output of a vertical-axis water turbine (VAWT) is presented.
Abstract: This study reports on an experimental method to obtain the motion law of a pitch system required for maximising the power output of a vertical-axis water turbine (VAWT). In order to allow for the close monitoring of blade forces, the turbine is modelled with a single oscillating hydrofoil in a water channel. The pitch motion is controlled numerically, and the pitch angle and forces are measured as a function of time. The objective of the optimisation is to maximise the time integral of the thrust coefficient. The optimisation is based on a hardware-in-the-loop method and uses a multi-scale, full-factorial approach. The optimal motion law is found through successive improvements with an adaptive parameter step refinement, while the integral of the driving force coefficient is used as a target function. An optimal pitch trajectory with a significant improvement in the thrust coefficient was obtained for a single operating point. The benefit of this methodology is the possibility to study a complete range of turbine designs through the variation of two dimensionless parameters (tip–speed ratio λ and reduced frequency k), within very short runtime, minimising time and costs investigation, compared to more common numerical methods, or experiments on a complete VAWT.

9 citations

Journal ArticleDOI
03 Feb 2021-Energies
TL;DR: In this article, the effect of flexible blades on the performance of a cross-flow turbine was investigated at the blade level using high-speed particle image velocimetry measurements.
Abstract: Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 15), quantifying the robustness of the turbine shape Both parameters are standard values for cross-flow tidal turbines Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall The flow field is investigated at the blade level using high-speed particle image velocimetry measurements Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines

6 citations


Cited by
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Journal Article
TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

01 Jan 2002
TL;DR: In this article, the aerodynamic design and performance of VAWTs based on the Darrieus concept is discussed, as well as future trends in design and the inherent socioeconomic and environmental friendly aspects of wind energy as an alternate source of energy.
Abstract: Wind energy is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal-Axis Wind Turbine (HAWT) or a Vertical-Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

549 citations

Journal ArticleDOI
19 Jun 2020-Energies
TL;DR: In this paper, the authors used the unsteady Reynolds averaged Navier-Stokes (URANS) approach with the k-ω shear stress transport (SST) turbulence model to estimate the H-Darrieus wind turbine aerodynamic performance, aerodynamic blade loads, and velocity profiles downstream behind the rotor.
Abstract: The purpose of this paper is to estimate the H-Darrieus wind turbine aerodynamic performance, aerodynamic blade loads, and velocity profiles downstream behind the rotor The wind turbine model is based on the rotor designed by McDonnell Aircraft Company The model proposed here consists of three fixed straight blades; in the future, this model is planned to be developed with controlled blades The study was conducted using the unsteady Reynolds averaged Navier–Stokes (URANS) approach with the k-ω shear stress transport (SST) turbulence model The numerical two-dimensional model was verified using two other independent aerodynamic approaches: a vortex model and the extended version of the computational fluid dynamics (CFD) code FLOWer All utilized numerical codes gave similar result of the instantaneous aerodynamic blade loads In addition, steady-state calculations for the applied airfoils were also made using the same numerical model as for the vertical axis wind turbine (VAWT) to obtain lift and drag coefficients The obtained values of lift and drag force coefficients, for a Reynolds number of 29 million, agree with the predictions of the experiment and XFOIL over a wide range of angle of attack A maximum rotor power coefficient of 05 is obtained, which makes this impeller attractive from the point of view of further research Research has shown that, if this rotor were to work with fixed blades, it is recommended to use the NACA 1418 airfoil instead of the original NACA 0018

23 citations

Journal ArticleDOI
15 Jan 2022-Energy
TL;DR: In this article, a passive flow control device with a local flexible membrane material over the suction surface was experimentally investigated with a smoke-wire experiment and time-dependent force measurement.

19 citations

Journal ArticleDOI
01 Jan 2022-Energy
TL;DR: In this article , a passive flow control device with a local flexible membrane material over the suction surface was experimentally investigated with a smoke-wire experiment and time-dependent force measurement in this study.

16 citations