Browsing by Author "VanSwieten, James H."
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- Development of a Driving Electric Dynamometer Rotor Emulator for MHK In‐Stream TurbinesLaing, William, E., Jr.; VanSwieten, James H. (2014-04)As marine and hydrokinetic (MHK) technologies which convert the flow of fluid into useful electrical power are developed, it is desirable to simulate drivetrain performance and refine control strategies in a laboratory prior to field installation. This paper presents and evaluates a technique developed to operate the prime mover of a dynamometer so that it drives a machine under test like an MHK turbine's rotor. The approach utilizes environmental and rotor numerical models to calculate hydrodynamic torque. Relationships between shaft torque, shaft speed, and variable frequency drive native torque reference were used to modify torque reference settings to achieve actual emulated torque values. The accuracy at which physical shaft torque matches theoretical hydrodynamic torque was then evaluated for three basic operating states: locked rotor, spin up/down, and variable flow operation. Percent‐error of averaged measured and theoretical shaft torque during simulation of these states was 9.7%, 5.5%, and 5.2%, respectively, demonstrating the success of applying the proposed technique.
- Evaluation of Hycom as a Tool for Ocean Current Energy AssessmentVanSwieten, James H.; Meyer, Imke; Alsenas, Gabriel M. (2014-04)This paper provides a global ocean circulation model based world-wide assessment of two flow characteristics and presents a direct comparison between model based predictions and in situ measurements in two regions. Four years (2009-2012) of HYbrid Coordinate Ocean Model (HYCOM)-generated data were used to estimate the average kinetic energy flux and flow direction variability in eight regions with time-averaged power density of at least 500 W/m². A direct comparison was then made between model calculated flow statistics those calculated from Acoustic Doppler Current Profiler data in both South Africa and the Southeast United States. Included analysis and discussion is intended to provide model predictions of the ocean current resource and assess the accuracy that can be expected when this model is used for making these predictions. This paper focuses on model predicted kinetic energy flux, flow speeds, and current direction variability, as these are important to the development and installation of OCT devices.