Consider two hydraulic turbines having identical specific speed and effective head at the inlet. If the speed ratio $$\left( {{{{N_1}} \over {{N_2}}}} \right)$$ of the two turbines is $$2,$$ then the respective power ratio $$\left( {{{{P_1}} \over {{P_2}}}} \right)$$ is _______________________.

The blade and fluid velocities for an axial turbine are as shown in the figure.

The magnitude of absolute velocity at entry is $$300$$ $$m/s$$ at an angle of $${65^0}$$ to the axial direction, while the magnitude of the absolute velocity at exit is $$150$$ $$m/s.$$ The exit velocity vector has a component in the downward direction. Given that the axial (horizontal) velocity is the same at entry and exit, the specific work (in $$kJ/kg$$) is ______________.

Kaplan water turbine is commonly used when the flow through its runner is

In order to have maximum power from a Pelton turbine, the bucket speed must be