Turbulence generation and its effect in LES approximations of tidal turbines
2013 (English)Conference paper (Refereed)
Tidal flows suitable for the installation of tidal stream turbines are highly turbulent with a broad range of turbulent scales, and intensities of around 10%. It is important to understand how turbulent flows affect the performance and wake profiles for the accurate prediction of the performance of single devices and arrays. Previous studies have considered the effects of turbulence intensity, but the effects of turbulent eddy size have not been investigated. This paper presents a new method for generating turbulence in large eddy simulations of uniform actuator disc rotor models. The advantage of the gridded actuator disc is that the generated turbulence may be controlled, so the effects of turbulence length scale and intensity may be investigated. Initial results show the wake recovery is faster behind a rotor generating larger turbulent length scales and intensities, with a corresponding increase in axial induction and thrust. Therefore turbines may be positioned closer together if they generate more turbulence, increasing the power output of an array for a given area, although the individual device performance may be lower. Future work will consider the effects of free-stream turbulence on the performance and wake profiles of the gridded actuator disc, and validation against experimental data.
Place, publisher, year, edition, pages
Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-222562OAI: oai:DiVA.org:uu-222562DiVA: diva2:711849
10th European Wave and Tidal Energy Conference (EWTEC)