Wind turbine blade with symmetrical tip, reflected radar phase change layer, tower edge and radar clutter processing methods.

摘要

A wind turbine blade 2 comprises a free end 5 and an end 6 attachable to a turbine shaft 4, a first surface 9 joining a second surface along a first edge 7 and a second edge 8 to define an airfoil section. At the free end a first aerofoil section portion from the first edge to the axis is symmetrical about the axis with a second aerofoil portion extending from the second edge to the axis. The blade may have a layer with wells based on incident radiation wavelength to induce a phase change and scattering. The turbine may comprise an even number of blades e.g. four or more. There are reflected radar signal processing methods for a turbine having an even number of blades to reduce clutter signal amplitude involving summing positive and negative doppler pulses, removing sub threshold positive and negative pulses from a clutter signal and comparison with a static clutter map. A non-circular turbine tower may have an edge e.g. be quadrilateral, a rhombus, diamond or kite shaped.