When the dependence of kinetic power on velocity is analysed,
it should be taken into account that at Q¼constant any change of
velocity v causes the change in flow cross-sectional area A.
Therefore, it is more correct to use the quadratic Eq. (3) instead
of cubic Eq. (4) P–v relationship for the analysis and illustration of
kinetic energy resources. A rapid increase in kinetic energy occurs
with the growth of velocity due to its quadratic relationship with
velocity in Eq. (3). This is shown in Fig. 1, where the P–v relationship
graph is given for Q¼1 m3
/s¼constant Similar plots, primarily
in the form of power density (kW/m2
)