Effects of turbulent flow conditions on performance of wind and tidal turbines

The UK is an abundant source of renewable power, especially in the wind and marine energy sectors. Onshore and offshore wind power contributes over 30 terawatt-hours (TWh) of electricity annually, equivalent to the electricity consumption more than 7 million homes. Wave and tidal devices that are currently being tested in the UK waters have a capacity of around 10MW, which is more than the rest of the world combined. All of these power-generating devices and associated moorings and foundations are affected by the turbulent conditions of the flow. These turbulent conditions are not only naturally present in the oncoming wind or water flow but are also generated by individual energy converters as the fluid flows past them. This leads to a turbulent flow regime that has a wide range of important length- and time-scales, which alter the shear profiles and turbulence intensities of the oncoming flow and has tremendous impact on the performance, fatigue and reliability of individual turbines and associated support structures. Turbulent conditions also play a significant role in altering the interaction in an array of devices, which in turn affect the overall energy generation potential of the farm.
In this project, the aim is to carry out a series of well-controlled experiments that will allow us to systematically examine the effects of shear and turbulence on all fluid dynamically relevant aspects of renewable energy generation. The goal is to characterise the variations in energy resource availability, power output, thrust, blade loads and the wake development of turbines for a variety of turbulent shear flow conditions. A unique flow facility that will be able to vary the characteristics of shear and turbulence independently will be used to generate different velocity profiles that retain a plethora of realistic flow characteristics. High-fidelity experiments using advanced laser diagnostics will be carried out to understand the interaction between these on-demand and repeatable turbulent shear flows and model-scale turbines, which will then allow us to isolate the effects of shear and turbulence on energy generation. This approach will enable us to validate and improve the current models as well as develop new methods that can identify new locations for energy farms, determine the performance and reliability of individual turbines and predict the output of entire wind and tidal arrays.