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. Therefore, in this study 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 develop arrays of hydrokinetic turbines 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 TriFrames serve as the building block for rapidly deploying multi-turbine arrays. The wake structure of a TriFrame of three model turbines is investigated. We employ large-eddy simulation (LES) along with fully resolving the turbine geometry details to simulate turbine-turbine wake interactions in the TriFrame configuration at lab-scale. First, the computed results are compared with experiments in terms of mean flow and turbulence characteristics with overall good agreement with bed-flume experiments. The flow-fields are then analyzed to elucidate the mechanisms of turbine interactions and wake evolution in the TriFrame configuration.
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. Three commercially viable designs of turbine rotor, developed by Verdant Power, were compared for power generation. The simulation-optimized design was selected for final deployment in tidal channel. This design was further tested for hydrodynamic characteristics.
Lastly, A large eddy simulation (LES)-based framework is used to investigate the site-specific flow dynamics past MHK arrays in a real-life marine environment. To this end, the unstructured Cartesian flow solver, coupled with a sharp interface immersed boundary method for 3D incompressible flows, is used. Multi-resolution simulations on locally refined grids are then 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. Comparison with the baseline flow in the East River reveal the effects of tidal array installation.
Bio: Saurabh is receiving his Ph.D. in Mechanical Engineering from University of Minnesota, Twin Cities. His research focus was Computational Fluid Mechanics where he used HPC tools to study Marine and Hydrokinetic (or MHK) Energy. He had obtained his Bachelors and Masters degrees in Mechanical Engineering as well from Indian Institute of Technology, Kanpur in India. He worked for one year in Oracle Corporation as Application Developer before going back to grad school on fellowship at University of Minnesota. At University of Minnesota, he led the computational research for the Roosevelt Island Tidal Energy (RITE) project which aims to install hydrokinetic turbines in New York City's East River. The code that he developed in Ph.D., enabled site-scale large-eddy simulation of the East River with a 30-turbine array. Saurabh is passionate about computational science as a tool to solve modern-day complex scientific and engineering problems and hopes to make an impact in the computational field.