# Cavitation Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Cavitation number is a dimensionless number that expresses the relationship between the difference of a local absolute pressure from the vapor pressure and the kinetic energy per volume.

## FORMULA

$$Ca = \frac { 2 \left(p \;-\;p_v \right) } {\rho v^2}$$

Where:

$$Ca$$ = Cavitation number

$$p$$ = local pressure

$$p_v$$ = fluid vapor pressure

$$\rho$$ = fluid density

$$v$$ = flow characteristic velocity

Solve for:

$$p = \frac {Ca \rho v^2} {2} \;+\; p_v$$

$$p_v = p \;-\; \frac {Ca \rho v^2} {2}$$

$$\rho = \frac { 2 \left (p \;-\;p_v \right)} {Ca v^2}$$

$$v = \sqrt { \frac { 2 \left (p \;-\;p_v \right)} {Ca v^2} }$$