Hamta, Armin2016-08-152016-08-152016http://hdl.handle.net/1993/31579A novel hydrokinetic turbine system is proposed to address key commercialization challenges facing the marine energy industry. Challenges include addressing icing issues by eliminating equipment that pierce the water/air interface; reducing the levelized cost of energy by simplifying demanding deployment and retrieval procedures; and positioning the turbine in the water column to maximize annual power production. Results of the experimental test matrix shows successful operation of the scaled counter-torque mechanism which operates with a 20 cm diameter rotor and is stabilized from the reactive nature of two point masses located at opposite ends of a spoke connected to the nacelle. Static and dynamic analytical modeling, computer aided design, manufacturing, and experimental testing of the prototype is the methodology that validates the operation of the counter-torquing mechanism. The prototype turbine is tested in a laboratory water tunnel at Reynolds numbers of 94 x 10^3, 104 x 10^3, and 115 x 10^3; with the generator loads ranging from free-wheeling to 6.2 W; and available counter-torque capacity varying from 0% to 40%. The maximum power coefficient obtained during the tests is 48.3% at a rotor tip speed ratio of 4.5. This research advances the Technology Readiness Level of the proposed novel turbine system from a level one to a level four based on the U.S. Department of Energy definition for technology development.enghydrokinetic turbinecounter-torque mechanismbuoymarinemaster thesis