Review of tidal turbine wake modelling methods

Abstract

Enabling Future Arrays in Tidal (EnFAIT) is an EU Horizon 2020 flagship tidal energy project. It aims to demonstrate the development, operation and decommissioning of the world’s largest tidal array (six turbines), over a five-year period, to prove a cost reduction pathway for tidal energy and confirm that it can be cost competitive with other forms of renewable energy. To determine the optimal site layout and spacing between turbines within a tidal array, it is essential to accurately characterise tidal turbine wakes and their effects. This paper presents a state-of-the-art review of tidal turbine wake modelling methods, with an overview of the relevant fundamental theories. Numerical and physical modelling research completed by both academia and industry are considered to provide an overview of the contemporary understanding in this area. The scalability of single device modelling techniques to an array situation is discussed, particularly with respect to wake interactions.

Computational Fluid Dynamics Study of Wake Recovery for Flow Across Hydrokinetic Turbine at Different Depth of Water

“…The quantity of surrounding ambient flow field will affect the rate of wake recovery. According to Jump et al, [9] and Gómez-Elvira et al, [22], wake recovery is the re-energisation process where the flow field recovers the lost velocity by transfer of momentum. Welty et al, [23] stated that the momentum would transfer from the faster moving layer to the slower moving layer.…”

“…Researchers [9,10] defined that wake of turbine is the rotationality of flow within the region downstream of the turbine which experiences disturbed flow that is characterized by the reduced flow speed, the pressure differential, expanding area, increase of turbulence and swirl. One of the terms commonly used to describe behaviors of wake is the wake recover.…”

“…One of the terms commonly used to describe behaviors of wake is the wake recover. Jump et al, [9] defined that wake recover is a formation of shear boundary layer between the low energy wake region and surrounding ambient flow that caused the momentum from surrounding flow field to be transferred back into the wake region. The wake is dissipated through this re-energization process and the flow field recovers the loss of velocity.…”

“…The wake is dissipated through this re-energization process and the flow field recovers the loss of velocity. Many studies [9,[11][12][13] related to wake recovery have been reported due to the significant impact of it on the performance of turbine. Wake recovery is the focus of researchers as wake recovery will affect the placement of turbine in array, especially the placement of hydrokinetic turbine.…”

On the wake of propeller hydrokinetic turbines: Numerical simulations and experiments

“…Most of the identification of the physical features of the wake flow in horizontal axis turbines are consolidated after a great number of previously published studies, concerning the fluid flow through based on wind turbines or large hydrokinetic turbines with small solidity (e.g. [14][15][16][17][18][19]), where the blockage effect is smaller, due to the geometry of the rotor with three sparse blades and often with a low rotation speed. However, there is a lack of research on high-solidity turbines, which are typically found in small hydrokinetic turbines.…”