What specific blade characteristic adjustment maximizes axial flow turbine efficiency under consistently decreasing tidal flow velocity?

To maximize axial flow turbine efficiency under consistently decreasing tidal flow velocity, the blade pitch angle must be continuously adjusted to maintain an optimal angle of attack. The blade pitch angle refers to the angle at which the turbine blade meets the incoming water flow. The angle of attack is the angle between the blade's chord line (an imaginary line from the leading edge to the trailing edge of the blade) and the relative water flow direction. As the tidal flow decreases, the ....