Turbine assembly

A transverse flow wind turbine assembly comprising, a rotor having a plurality of blades, and a shroud comprising at least three shroud portions, said shroud portions extending axially along the rotor and around the rotor to at least partially enclose the rotor, and said shroud portions being rotationally adjustable in order to expose a portion of the rotor to the wind, and wherein the shroud, in use, defines a variable inlet and a variable outlet, and wherein, in use, the inlet area and outlet area are variable independently of each other in area and in angular position around the circumference of the turbine, and wherein adjustment of the area of the inlet area does not result in the same magnitude of adjustment in area of the outlet area, and wherein adjustment of the position of the inlet area does not result in the same magnitude of adjustment of the position of the outlet area.