Characteristic Velocity

Characteristic velocity, abbreviated as U, measure the effectiveness of the combustion of a rocket engine at high temperature and pressure, seperate from nozzle performance.  It is used to compare different propellant and propulsion systems.

 

Characteristic velocity formula

\(\large{ U = \frac { p_c \; A } { \dot m_f }  }\)

Where:

Units	English	Metric
\(\large{ U }\) = characteristic velocity	\(\large{\frac{ft}{sec}}\)	\(\large{\frac{m}{s}}\)
\(\large{ A }\)  (Greek symbol rho) = area of throat	\(\large{ft^2}\)	\(\large{m^2}\)
\(\large{ \dot m_f }\) = mass flow rate	\(\large{\frac{lbm}{sec}}\)	\(\large{\frac{kg}{s}}\)
\(\large{ p_c }\) =  pressure of chamber	\(\large{\frac{lbf}{in^2}}\)	\(\large{Pa}\)

 

Related Characteristic Velocity formulas

\(\large{ U =  \sqrt{  2  \;  Ec \; c \;  \Delta T     }    }\)	(Eckert number)
\(\large{ U =  \sqrt{  \frac{\Delta p}{Eu \;  \rho}  }  }\)	(Euler number)

Where:

\(\large{ U }\) = characteristic velocity

\(\large{ \rho }\)  (Greek symbol rho) = density

\(\large{ Ec }\) = Eckert number

\(\large{ Eu }\) = Euler number

\(\large{ c }\) = specific heat

\(\large{ \Delta T }\) = temperature change