1. Northwest National Marine Renewable Energy Center NW National Marine Renewable Energy Center Turbine Performance and Wake Prediction Alberto Aliseda, Sylvain Antheaume, Teymour Javaherchi, Joseph Seydel Department of Mechanical Engineering University of Washington NOAA Northwest Fisheries Science Center 12/08/2009

2. Northwest National Marine Renewable Energy Center Device Performance and Wake Modeling Fluid Mechanics Modeling: - flow around turbine blades - flow in the turbine wake - wake-turbine interactions - wake-wake interactions

3. Northwest National Marine Renewable Energy Center Device Performance and Wake Modeling We use a hierarchy of numerical models for simulation of different aspect of the physics: - Porous Disk: Drag and Energy Dissipation - Virtual Blade Model: Axisymmetric and Steady - S/M Reference Frame: Navier-Stokes in a rotating reference frame - Moving Mesh: Full blade representation.

4. Northwest National Marine Renewable Energy Center Device Performance Modeling Performance Modeling is needed to optimize power extraction: - Blade design - Depth optimization - Tip speed ratio y/b = 0.3 y/b = 0.47 y/b = 0.63 y/b = 0.8y/b = 0.95

5. Northwest National Marine Renewable Energy Center Wake Modeling Because of the concentrated nature of tidal energy, understanding the wake-turbine and wake-wake interactions is key to the development of this technology. Turbine spacing rules developed for wind farms can not easily be extended to tidal. They are empirical, not derived from first principles and not formulated in terms of non-dimensional parameters.

6. Northwest National Marine Renewable Energy Center Wake Modeling: Near Wake The near wake has important technological and environmental effects: - Sediment scouring by high speed tip flows - Bio effects of pressure fluctuations in tip vortices: fish bladder.

7. Northwest National Marine Renewable Energy Center Wake Modeling: Near Wake

8. Northwest National Marine Renewable Energy Center Wake Modeling: Far Wake The far wake has a dominant role in turbine array design and estuarine dynamics: - Efficient turbine spacing in narrow high kinetic energy channels - Stratification and mixing in tidal channels - Estuarine circulation: flow exchange, nutrient and oxygen concentrations.

9. Northwest National Marine Renewable Energy Center Wake Modeling: Far Wake

10. Northwest National Marine Renewable Energy Center Wake Modeling: Far Wake

11. Northwest National Marine Renewable Energy Center Turbine Modeling: Experimental Validation Plans to build a large-scale hydrodynamic testing facility