INVESTIGATION ON TIDAL TURBINE ARRAYS WITH A COUPLED DES-BEM MODEL

In order to develop tidal current energy, the effect turbines have on their surrounding flow and how these devices perform when installed in an array need to be better understood. This requires studying the hydrodynamics related to tidal turbines and their wakes. Detailed information on flow charact...

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Detalles Bibliográficos
Autor: Gajardo-Orellana, Daniel Ignacio
Tipo de recurso: tesis de maestría
Estado:Versión publicada
Fecha de publicación:2017
País:Chile
OAI Identifier:oai:repositorio.anid.cl:10533/232839
Acceso en línea:https://hdl.handle.net/10533/232839
Access Level:acceso abierto
Palabra clave:Ingeniería y Tecnología
Ingeniería Civil
Descripción
Sumario:In order to develop tidal current energy, the effect turbines have on their surrounding flow and how these devices perform when installed in an array need to be better understood. This requires studying the hydrodynamics related to tidal turbines and their wakes. Detailed information on flow characteristics is needed to comprehend wake interaction and changes on the ambient flow due to tidal turbines. However, there have been limited approaches that are able to analyze multiple tidal turbines simultaneously. Here we propose a numerical methodology that couples Blade Element Momentum (BEM) with Detached- Eddy Simulation (DES) to simulate tidal turbine arrays and obtain detailed information on the mean and instantaneous flow. Simulations are carried out using real rotor data and validated with existing experimental and modeled results on three different array configurations. The model shows good correlation with experimental mean flow profiles and turbine performance measurements. We show that wakes of downstream turbines are characterized by higher levels of turbulence and temporal fluctuations than upstream turbine ones. Downstream regions show higher levels of turbulent kinetic energy and Reynolds stresses, along with stronger presence of vortical structures. The more complex flow faced by downstream turbines produced lower power and thrust coefficients on them. Moreover, performance measurements and induced bed shear stress showed considerably higher temporal fluctuations for posterior rows in the studied arrays. These results help understand the behavior of turbines in an array and how their performance and impacts change when devices function together. Furthermore, the proposed methodology is validated for its use on different array configuration and turbine designs.