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Are Nearly all Tidal Stream Turbines Designs Wrong for the Pentland Firth? Stephen Salter Institute for Energy Systems University of Edinburgh S.Salter@ed.ac.uk www.see.ed.ac.uk/~shs Slide 2 No names, no pack drill. Slide 3 Edinburgh vertical-axis, variable-pitch with rim power take off. EWTEC Patras 1998 Slide 4 ... just like wind turbines but under water. Frederick Lanchester 1868-1946 Albert Betz 1885-1968 Slide 5 Turbine in a duct: Slide 6 Open flow field Duct Slide 7 Slide 8 Slide 9 McAdam RA, Houlsby GT, Oldfield MLG. Experimental measurements of the hydrodynamic performance and structural loading of the transverse horizontal axis water turbine: part 1. Renewable Energy vol. 59 pp. 105-114. 2013 Slide 10 ODoherty DM. Mason-Jones, Morris, ODohertyT, Bryne, Pricket, Grosvenor. Interaction of Marine Turbines in Close Proximity. EWTEC 2011 Slide 11 Slide 12 Slide 13 Slide 14 NASA Slide 15 Edinburgh vertical-axis, variable-pitch with rim power take off. EWTEC Patras 1998 Slide 16 Flow Impedance The determination of the water to flow despite the introduction of obstacles. Slide 17 Flow Impedance The determination of the water to flow despite the introduction of obstacles. Ratio of head increase to flow-rate reduction. Slide 18 Flow Impedance The determination of the water to flow despite the introduction of obstacles. Ratio of head increase to flow-rate reduction. Slide 19 Flow Impedance The determination of the water to flow despite the introduction of obstacles. Ratio of head increase to flow-rate reduction. Slide 20 Flow Impedance The determination of the water to flow despite the introduction of obstacles. Ratio of head increase to flow-rate reduction. Slide 21 Flow Impedance The determination of the water to flow despite the introduction of obstacles. Ratio of head increase to flow-rate reduction. Slide 22 Laminaria Hyperborea (kelp) are found along the edges of the Pentland Firth at depths up to 30 m. Length can reach 3.5 metres. Cf = ? Slide 23 Pentland bed stills. P Hayes. Fisheries Research Aberdeen 2006-8 68 mm bob Slide 24 Friction coefficients for Fshear = 0.5 U 2 Cf 6.165 TW x 0.04 = 247 GW Slide 25 Slide 26 Slide 27 Slide 28 GOOGLE IMAGES MoD order the stretcher bearers to be at the same end ? Slide 29 Slide 30 Slide 31 Slide 32 Slide 33 No tip-to-hub velocity reduction No squeezing torque through a bearing. On-line shirt-sleeve access at the surface. Thousands of force lines. Contact-free gutter seal. Lots of space. Slide 34 Slide 35 Slide 36 Slide 37 Slide 38 Are Nearly all Tidal Stream Turbines Designs Wrong for the Pentland Firth? Stephen Salter Institute for Energy Systems University of Edinburgh S.Salter@ed.ac.uk www.see.ed.ac.uk/~shs Slide 39 Google images Slide 40 Speed up x 30 Range up x 6000 Payload up x 20,000 Cost per ton-mile down 100 Google images Slide 41 Something for the simpletons Slide 42 Slide 43 R.A. McAdam, G.T. Houlsby, M.L.G. Oldfield Structural and Hydrodynamic Model Testing of the Transverse Horizontal Axis Water Turbine EWTEC 2011 Slide 44 ODoherty DM. Mason-Jones A, Morris C, ODohertyT, Bryne C, Pricket PW, Grosvenor RI. Interaction of marine turbines in close proximity. EWTEC 2011 Slide 45 Slide 46 No names, no pack drill. Slide 47 Slide 48 Slide 49 R.A. McAdam, G.T. Houlsby, M.L.G Oldfield. Structural and Hydrodynamic Model Testing of the Transverse Horizontal Axis Water Turbine. EWTEC 2011