NOVELTY - The turbine rotor assembly (1) has a hub rotatable about a central axis. Blades (4) are mountable to the hub about the central axis. Each blade has a leading edge (11) and a trailing edge. The leading edge and trailing edge are configured to be complementary in profile to each other, such that the blades can be mounted in close fitting edge-to-edge proximity to each other. The blades may be arranged sequentially to form a circular array about the central axis, or in a non-overlapping sequential formation.    USE - Turbine rotor assembly for extracting energy from oscillating working fluid. Can be used in an ocean wave energy extraction system (claimed) employing an oscillating water column (OWC), and can be used in turbines (claimed) such as unidirectional reaction turbines.    ADVANTAGE - Provides an increased surface area to enable a working fluid to pass across more blade surface which in turn improves the efficiency of the thrust arising from the lift forces generated by the working fluid flowing over the blade and accelerating through the nozzle, in which the thrust acts to rotate the hub and blades about the central axis. Ensures improved efficiency due to improved pressure profile across each blade. Magnifies the amplification of the OWC, thus increasing the amount of pneumatic power extracted and improving the efficiency of the turbine. Enables increased amounts of energy to be extracted from an oscillating or bidirectional working fluid. Provides a turbine rotor assembly with blades that advantageously provide an increase frontal area of the turbine blades which constricts the fluid flow passage to create a greater pressure differential across the blades, resulting in increases in the lift and thrust forces being applied to the blades. Ensures that the close fitting edge-to-edge proximity of the blades also advantageously provides for nozzles which can increase the velocity of the airflow, again increasing the pressure difference across the blade with a resultant increase in thrust.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view of the turbine rotor assembly.    Turbine rotor assembly (1)    Blades (4)    Cylindrical housing (9)    Leading edge of each blade (11)