Bio: F. Pons is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Turbine & Potential flow. The author has an hindex of 2, co-authored 4 publications receiving 34 citations.
TL;DR: In this paper, the performance and flow evaluation for a low-speed hydrokinetic turbine of Darrieus type, operating in a confined flow channel is presented, which includes computations (2D CFD) using Chimera meshes and experiments including phase-locked measurements.
TL;DR: A kinematics-based method is described, through which the pitching motion of the blades varies in such a way that the flow is controlled around them as well as across the rotor, to derive the blade pitching laws being compatible with the unsteady Kutta-Joukowski condition.
Abstract: The circulation control around the Darrieus turbine blades is considered as a significant practical solution so as to improve the machine's performance. This paper describes a kinematics-based method, through which the pitching motion of the blades varies in such a way that the flow is controlled around them as well as across the rotor. For this purpose, the potential flow approach is used to derive the blade pitching laws being compatible with the unsteady Kutta-Joukowski condition at the trailing edge of the blade. By means of this, a constant circulation around the blade is ensured. Preliminary CFD investigations have evidenced the operating conditions at which the constant-circulation framework may be applied to turbulent flows in order to control the vortex shedding and avoid blade-vortex interactions. Nonetheless, a strict application of this concept prevents the turbine from harvesting the energy. As an alternative strategy, the application of a locally variable-circulation is proposed in order to enhance the power output without compromising on flow control. Three major accomplishments of the variable-circulation-based blade pitching proposition are the following: a. flow control around the turbine blades with definite patterns of vortical structures, b. consistent increase in the turbine's coefficient of power, and c. widened operating range of the turbine.
TL;DR: In this article, the authors present an extension of the application of conformal mapping to produce the time-dependent flow over a rotating turbine blade in order to develop a quantified relationship between the blade orientation with respect to the rotor's tangent and its rotational motion.
Abstract: Analytical and computational studies of flow across a low-speed marine turbine of Darrieus type with pitching blades have been carried out for flowfield and performance evaluation. The objective of this study is to develop efficient blade pitching laws to arrest or control the vortex shedding from the blades during turbine’s operation. This is achieved by imparting an arbitrary constant amount of circulation to the blades, where Kelvin’s theorem is respected. This paper presents the extension of the application of conformal mapping to produce the time-dependent flow over a rotating turbine blade in order to develop a quantified relationship between the blade’s orientation with respect to the rotor’s tangent and its rotational motion. The flow development is based on the analytical treatment given to potential flow formulation through Laurent series decomposition, where the Kutta condition is satisfied. The pitch control law and the analytical modeling of the hydrodynamic forces acting on the blade are der...
TL;DR: It is observed that the uncertainty in the turbine's rotation is more influential on the power output compared to free-stream velocity, and the sensitivity of the turbine’s performance to these input uncertainties is quantified using probability methods, including response surface, PDF and CDF.
TL;DR: The methods and results of this paper provide a perspective to multi-time scales modeling of hydro-turbine governing system and contribute to the optimization analysis and control of the system.
TL;DR: In this paper, an up-to-date review of the potential, technologies, prototypes, installed capacities, and projects related to ocean renewable energy including wave, tidal, and thermal, and salinity gradient sources.
Abstract: This study, firstly, provides an up-to-date global review of the potential, technologies, prototypes, installed capacities, and projects related to ocean renewable energy including wave, tidal, and thermal, and salinity gradient sources. Secondly, as a case study, we present a preliminary assessment of the wave, ocean current, and thermal gradient sources along the Brazilian coastline. The global status of the technological maturity of the projects, their different stages of development, and the current global installed capacity for different sources indicate the most promising technologies considering the trend of global interest. In Brazil, despite the extensive coastline and the fact that almost 82% of the Brazilian electricity matrix is renewable, ocean renewable energy resources are still unexplored. The results, using oceanographic fields produced by numerical models, show the significant potential of ocean thermal and wave energy sources in the northern and southern regions of the Brazilian coast, which could contribute as complementary supply sources in the national electricity matrix.
TL;DR: In this paper, the performance of hybrid rotor cross flow hydrokinetic has been investigated for different rotor parameters, including power coefficient and torque coefficient, and it has been found that radius ratio and attachment angle play a crucial role in performance enhancement with reduction in torque fluctuations.
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.
TL;DR: An inclusive analysis not only explores the hydrodynamics in the commercial culture tanks with Cornell-type dual-drain but also recommends the farmers with the suitable flow-split between such outlet systems.