Tidal Hydrodynamics

Credit: Guy HoulsbyThe group is conducting research to understand how much tidal power can be extracted from a variety of coastal basins and what effect power extraction will have on the natural hydrodynamics within these basins. The group is using both analytical and numerical modelling to investigate this, both for idealised groups of turbine, idealised coastal geometries, and for possible sites for tidal energy extraction around the United Kingdom.

Axial Flow Devices

Credit: Jianxin HuThe effect of realistic conditions of the underwater environment on the performance of generic axial flow tidal energy converters is being thoroughly investigated through a range of analytic and numerical models. Computational CFD analyses are conducted using actuator disk, CFD-embedded blade element actuator disk, actuator line, and blade resolved analyses. Components of ocean flow such as surface waves, velocity profile, large and small scale turbulence and yawed flow are modelled, and their influences on both bare and ducted turbines are examined.

Cross-Flow Turbine Hydrodynamics

THAWTThe group conducts research to investigate the hydrodynamic performance of tidal turbines; both generic devices as well as a specific proprietary device being developed at Oxford. This project is part of a consortium of research activities at Oxford that are collectively investigating the feasibility of a Transverse Horizontal Axis Water Turbine (THAWT) to extract energy from tidal streams. This project’s contribution to the THAWT project is centred on an extensive CFD investigation aimed at furthering the understanding of flows through generic cross-flow turbines and at improving THAWT's hydrodynamic performance.

Advanced Turbine Concepts

Duct velocity fieldSimulation of flows through ducted and open-centre horizontal axis turbines, as well as the interaction between turbines and floating platforms, form another part of the research conducted within the group. This research project extends the range of turbine concepts under investigation to include further novel advanced concepts currently proposed by the industry. The goal of this project is to determine, through theoretical modelling, numerical simulation and small-scale experiment, the fluid mechanics behaviour and performance of ducted and open-centre turbines and the performance of turbines in relation to the dynamics floating platforms. Furthermore, the project will seek to optimise such novel turbine concepts through the improved understanding of the flow and the theoretical flow models developed during the project.

High Order Computational Fluid Dynamics

Credit: Esteban FerrerThe group is developing a high order discontinuous Galerkin finite element code, DG@Tidal with a moving mesh capability for simulation of flow problems in which flux conservation is problematic. Of particular interest are flows through tidal turbines in which sliding domain interfaces are present. The method allows for accurate preservation of interface fluxes as well as being able to predict the effects of freestream turbulence and wake development in turbine efficiency.