approximates the gaseous energy produced by the igniter up to time zero. The time

The term

function *H(t) *is added to make the equation balance. This quantity usually is identified with the energy lost

to the walls of the device and leakage during the ballistic cycle. However, in addition to the dissipated

energy, this term also includes errors inherent in the other terms of the equation.

(2) *Equations of motion.*

† The form function is a property of the charge which describes the amount of gas produced with the burning of a given

fraction of the propellant web.