Numerical simulation of the wake of marine current turbines with a particle method

Abstract

This paper presents numerical computations of three bladed horizontal axis marine current turbines in a uniform free upstream current. The unsteady evolution of the turbine wake is taken into account by some three-dimensional software, developed to assess the disturbances generated in the sea. An unsteady Lagrangian method is considered for these computations using "Vortex Method"; a velocityvorticity numerical implementation of the Navier-Stokes equations. The vortex flow is discretised with particles carrying vorticity, which are advected in a Lagrangian frame. The present paper aims at presenting results on both power and thrust coefficient (C P and C T) predictions and wake characterisation, up to ten diameters downstream of the turbine. Moreover, two different marine current turbines configurations are considered: one is taken from literature [1] and the second one is an open-modified version of turbine inspired from previous works [2]. Highlights ► We developed a numerical software for the computation of marine current turbine. ► We used an unsteady Lagrangian implementation of the Navier-Stokes equations. ► Two different turbines are considered, one of them is taken from the literature [1]. ► Both power/thrust coefficients and wake are computed with the same numerical tool. ► All the numerical results are compared to experiments

Simulating the Wake Downstream of a Horizontal Axis Tidal Turbine Using a Modified Vorticity Transport Model

“…Although this technique is not new, it has been utilized to study the wake of a tidal turbine only recently. Pinon et al [7] have implemented a particle representation of the wake vorticity down-stream of a horizontal-axis tidal turbine in a uniform current. The numerical results indicate however a high level of numerical dissipation in comparison with experimental data [7].…”

Hydrodynamic modelling of marine renewable energy devices: A state of the art review

“…Numerical results include pressure and loads distributions on turbine blades and flow-field quantities for given current speed and different values of the Tip Speed Ratio (TSR). Pinon et al (2012) propose a computational study of a horizontal axis turbine by a methodology based on a velocity-vorticity formulation of the Navier-Stokes equations. Turbine blades are not explicitly simulated, but their effect on the flow is accounted for through forcing terms in the momentum equation.…”

Etude expérimentale et numérique du comportement d’hydroliennes à axe horizontal

“…Le code de simulation numérique de l'écoulement autour d'une ou plusieurs hydroliennes utilise la méthode vortex qui repose sur une description Lagrangienne de l'écoulement comme présenté en détail dans (PINON et al, 2012). La méthode vortex utilise les équations de Navier-Stokes en formulation vitesse/tourbillon.…”

“…Ceci s'explique par la méthode utilisée pour modéliser les pâles de la turbine, qui ne permet pas de prendre en compte les décollements sur les profils de pales (PINON et al, 2012). Afin d'étudier l'influence du TSR sur le sillage d'une hydrolienne, des mesures par vélocimétrie laser ont été effectuées à TSR=2,5 et TSR= 3,67, soit respectivement à un point de fonctionnement sous le régime nominal et au point de fonctionnement nominal de la turbine considérée.…”