Tidal Energy Research – Laboratory Experiments, Simulations, and Open-Water Deployments

Martin Wosnik
Associate Professor

UNH Dept. Mechanical Engineering
Center for Ocean Renewable Energy (CORE)

Friday, Oct. 19, 2018, 3:10pm
Chase 105

Ocean renewable energy research at the UNH Center for Ocean Renewable Energy (CORE) spans various scales, levels of complexity and environments – from the “blade scale.” to tests in a tow/wave tank or wind tunnel, to deployments of instrumented process models at open-water test sites.

The focus of this presentation will be on tidal energy research, and more specifically on marine hydrokinetic (MHK) energy conversion. Cross-flow turbines, or vertical-axis turbines, have shown potential in both MHK and wind energy applications. For individual turbines, the research focus is often on evaluating and/or predicting performance and loads, whereas for turbine array layouts the focus is on maximizing overall power output while minimizing impact, i.e., understanding turbine wakes and minimizing their interference, or taking advantage of constructive wake interaction.

Experiments were carried with large laboratory-scale cross-flow turbines, D~O(1m), using a high-resolution turbine test bed in a large cross-section tow tank, designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. Turbines of varying solidity were employed, including the UNH Reference Vertical Axis Turbine (RVAT) and a 1:6 scale model of the DOE-Sandia Reference Model 2 (RM2) turbine. To improve parameterization in array simulations, an actuator line model (ALM) was developed to provide a computationally feasible method for simulating full turbine arrays inside Navier-Stokes models. Results are presented for the simulation of performance and wake dynamics of axial- and cross-flow turbines and compared with experiments and body-fitted mesh, blade-resolving CFD.

Examples of open-water deployments of MHK turbines will be shown, including the recent deployment of a 3.2m diameter cross-flow turbine at Memorial Bridge in Portsmouth, NH as part of the “Living Bridge” project (NSF, FHWA, NHDOT, DOE), which created a self-diagnosing, self-reporting “smart bridge” powered by a locally available renewable energy source, tidal energy.

Of Interest to UNH CCOM/OE
Significant new research infrastructure for marine energy research has been brought online at UNH in the past few years: a new tow mechanism, turbine test bed and wake traversing system for the tow tank; a small high-speed cavitation tunnel; two tidal energy test platforms, including a new 50’ x 20’ platform recently deployed at Memorial Bridge in Portsmouth, NH; a large boundary layer wind tunnel. Two estuarine tidal energy test sites and an off-shore test have are being used for tidal and wave energy converter deployments.


Prof. Martin Wosnik joined the UNH Mechanical Engineering faculty in the spring of 2008. Before coming to UNH, he worked as Assistant Research Professor in the Thermo and Fluid Dynamics Section at Chalmers University of Technology in Gothenburg, Sweden, then as Research Associate at St. Anthony Falls Laboratory at the University of Minnesota. Before coming to New Hampshire, Prof. Wosnik was Senior Flow Engineer at Alden Research Laboratory in Massachusetts, a national flow engineering firm conducting a wide variety of hydraulic studies for electric power utilities, architect-engineering firms, equipment manufacturers, and governmental agencies.

Prof. Wosnik’s research interests are in the area of fluid and thermal sciences with an emphasis on renewable energy applications, including ocean renewable energy (tidal, wave, wind), turbulent flows, high-speed hydrodynamics, cavitation, flow measurement and hydraulic modeling.