Browsing by Author "Fabien, Brian"

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    Control of a Helical Cross‐Flow Current Turbine
    Cavagnaro, Robert; Fabien, Brian; Polagye, Brian (2014-04)
    Adaptive control strategies utilizing preview information of upstream velocity are promising approaches for enhancing performance and reducing loads on hydrokinetic turbines. A control scheme relating a turbine's characteristic performance curve and rotation rate to an optimal torque setpoint is implemented experimentally and in simulation for a laboratory‐scale helical cross‐flow turbine. Energy extraction performance for schemes employing adaptive/preview techniques is compared to performance under constant speed and non‐adaptive control. Results in simulation indicate significant improvement over constant speed operation and modest improvement over non‐adaptive strategies. Experimental results for adaptive strategies are comparable to non‐adaptive strategies, due to uncertainty in instantaneous performance curves.
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    Dynamic Modelling of Compliant-Moored Submerged Systems with Applications to Marine Energy Converters
    Nichol, Tyler; DuBuque, Geoff; Fabien, Brian (2014-04)
    This paper presents a full‐range‐of‐motion numerical model of the dynamic characteristics of compliant‐moored submerged systems in unsteady fluid flow using a first‐principles approach. The program, implemented using the MATLAB software package, is in development with the primary intention of being applicable to in‐stream hydrokinetic turbines, though many wave energy converter and offshore wind turbine platform systems will also be capable of being modeled. A Lagrangian frame of reference is adopted to generate the equations of motion of a given system. The external forces presently considered in the model are those of gravity, buoyancy, and fluid drag, with plans to include more sophisticated fluid effects as the project advances. The development of the kinematic system and the body drag model are discussed. Additionally, two validation tests are presented. The results of the validation tests provide confidence that the methods employed have the potential to realistically simulate the dynamic behavior of compliant-moored systems once more detailed effects of fluid loading are accounted for.