1. The previous investigations have been both experimenta 12-18 and theoretical .11.15,19-25 The experimental investigations examined many of the possible influences i n burning rate. The 'nvestigations were on f u l l scale motors,3,5 subscale motors 2.6,8 and propellant slabs s r a n d s . , 9 - 1 The results of these produced some general conchsions about
2. perpend: iicn-ases t o 30-60".
3. The gas dynamic mode has also received substantial attention i n the past. Most of this has been focused on the swirling of gas through nozzles.26-35 When a solid rocket motor is spun about it P longitudinal axis, a swirling motion is i.mparted t o the flow which is carried through the nozzle. The effect of this Swirling flaw is to decrease the mass flow through the nozzle. This has the same effect on the nozzle's performance as reducing the throat area. Indeed, imparting a swirling motion t o the flow has heen suggested as one way t o artificial.ly vary the throat area in nozz 1es.26
4. Very little attention has been focused on the gas dynamic changes in the motor's combustion chamber. GlickZ1 f i r s t looked at the problem i n 1966 but little has been done since. Recentl.y, however, Sf 0rzini 3has investigated the effect on gas dynamics due to longitudinal motor accelerations. That investigation found that ignoring the longitadinal body forces on the gases in the chamber and through the nozzle resulted in a small effect on motor specific impulse. This effect w i l l be greatest in motors with large chamber volumes and Sforzini's analysis showed only a 0.22% degradation in average inpulse for the space shottle SRll 5pecj.fi.c