# Hydraulic Efficiency

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Hydraulic efficiency, abbreviated as $$n_h$$, a dimensionless number, is the ratio of hydrodynamic energy in the form of fluid to the amount of mechanical energy delivered to the rotor.

## Hydraulic Efficiency Formula

 $$\large{ n_h = \frac{ Q_a \; 100 }{ Q_t } }$$

### Where:

 Units English Metric $$\large{ n_h }$$ = hydraulic efficiency $$\large{dimensionless}$$ $$\large{ Q_a }$$ = actual flow rate output $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$ $$\large{ Q_t }$$ = theoretical flow rate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$