Multi-resolution Modeling and Simulation of Marine Hydrokinetic Turbine Arrays
Marine and hydro-kinetic (MHK) energy hold promise to become significant contributor towards sustainable energy generation. Despite the promise, commercialization of MHK energy technologies is still in the development stage. While many simplified models for MHK site resource-assessment exist, more research is needed to enable efficient energy extraction from identified MHK sites. A marine energy company named Verdant Power Inc. was granted first federal license to install up to 30 axial hydrokinetic turbines in the East River in New York City under what came to be known as Roosevelt Island Tidal Energy (RITE) project. In this research, we investigate issues of relevance to post-site-identification stage for a real-life tidal energy project, the RITE project, using high-fidelity numerical simulations.
An effective way to rapidly deploying multi-turbine arrays in river and tidal channels is to arrange them in TriFrame configurations where three turbines are mounted together at the apexes of a triangular frame. The wake structure of a TriFrame of three model turbines is investigated. We employ large-eddy simulation (LES) to simulate turbine-turbine wake interactions in the TriFrame configuration. The wakes of the TriFrame turbines is compared with that of an isolated single turbine wake to further illustrate how the TriFrame configuration affects the wake characteristics and power production in an array of TriFrames. The power produced by individual turbines was also studied to guide the optimum turbine rotor blade design. Several turbine rotor blade designs were investigated using ultra high resolution three-dimensional simulation at field scale.
Lastly, we propose a large eddy simulation (LES)-based framework to investigate the site-specific flow dynamics past MHK arrays in a real-life marine environment. A new generation unstructured Cartesian flow solver, coupled with a sharp interface immersed boundary method for 3D incompressible flows, is used. Optimized data-structures and efficient algorithms were developed to enable faster simulation on high-resolution grids. Multi-resolution simulations on locally refined grids are employed to model the flow in a section of the East River with detailed river bathymetry and inset turbines at field scale. The results are analyzed in terms of the wake recovery and overall wake dynamics in the array.