# Water Hammer Fluid Velocity Change

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

## Water Hammer Fluid Velocity Change Formula

 $$\large{ \Delta v = \frac { h_{spf} g } { \alpha } }$$ (maximum surge pressure head) $$\large{ \Delta v = \frac{ 144 \;p_{spf} \; g }{ \alpha \; \gamma_f } }$$ (maximum surge pressure for a fluid) $$\large{ \Delta v = \frac{ 2.31 \;p_{spw} \; g }{ \alpha } }$$ (maximum surge pressure for a water)

### Where:

 Units English Metric $$\large{ \Delta v }$$ = fluid velocity change $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ $$\large{ g }$$ = gravitational acceleration $$\large{\frac{ft}{sec^2}}$$ $$\large{\frac{m}{s^2}}$$ $$\large{ p_{spf} }$$ = maximum surge pressure for fluid $$\large{\frac{lbf}{in^2}}$$ $$\large{Pa}$$ $$\large{ p_{spw} }$$ = maximum surge pressure for water $$\large{\frac{lbf}{in^2}}$$ $$\large{Pa}$$ $$\large{ h_{spf} }$$ = maximum surge pressure head in length of fluid $$\large{\frac{lbf}{in^2}}$$ $$\large{Pa}$$ $$\large{ \alpha }$$  (Greek symbol alpha) = pressure wave velocity $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ $$\large{ \gamma_f }$$  (Greek symbol gamma) = unit weight of fluid $$\large{\frac{lbm}{ft^3}}$$ $$\large{\frac{N}{m^3}}$$ 