Dynamic Modeling of Hydrokinetic Energy Extraction

Abstract

The world is facing an imminent energy crisis. In order to sustain our energy supply, it is necessary to advance renewable technologies. Despite this urgency, however, it is paramount to consider the larger environmental effects associated with using renewable resources. Hydropower, in the past, has been seen as a viable resource to examine, given that its basics of mechanical to electrical energy conversion seem to have little effect on the environment. Discrete analysis of dams and in-stream diversion set-ups, although, has shown otherwise. Modifications to river flows and changes in temperature (from increased and decreased flows) cause adverse effects to fish and other marine life because of changes in their adaptive habitat. Recent research has focused on kinetic energy extraction in river flows, which may prove to be more sustainable, as this type of extraction does not involve a large reservoir or large flow modification. The field of hydrokinetic energy extraction is immature; little is known about the devices’ performance in the river environment and their risk of impingement, fouling, and suspension of sediments. The governing principles of hydrokinetic energy extraction are presented, along with a two-dimensional computational fluid dynamics (CFD) model of the system. Power extraction methods are compared and CFD model validation is presented. It is clear that more research is required in hydrokinetic energy extraction with an emphasis toward lower environmental and ecological impacts.

Computational Fluid Dynamic Simulation of Vertical Axis Hydrokinetic Turbines

“…Additionally, since LES and DNS methods require very fine grids for wall-bounded flows, they are still in development stages for high Reynolds number flow; therefore, they are not practical for modeling the flow around the hydrokinetic turbine. An alternative for CFD simulation is the use of unsteady Reynolds-averaged Navier-Stokes (URANS) turbulence models, which are computationally economical and of great use among both industry and academia in comparison with LES models [41,42,[44][45][46][47][48][49][50].…”