1. CLASS TYPE FREOUENCY RANGE (cps) LOW Chugging 0-10
2. 10-200 POCO Medium ACOUOUC 20 -1000
3. Oxidizer atomization and mixing phenomenoninstabilitiesaresomewhatrelatedto instabilities found in vaporization-limited liquid propellantrocketsbut tend tobe somewhatmore complex. Forhybrids they areindicatedby low frequency(5-19 cps).chuggingtype oscillations. Observations of this type of instability are discussed in References 2, 4. and 5. This mechanismgenerally operates in regimesoflow oxidizer massfluxandlowchamberpressure.6
4. This instability is typically recognizable by low frequency (1-100 cps) pressure oscillations that do notappeartobe coupled to any chamber dimension,a thickcharorsootlayerbuildupon the burned fuel grain surface, and brightness variation ofthemotorexhaustwithejectedsolid matter. Figure 7 shows the pressure-time trace of typical chuffing instability behavior. This type of instabilityis usuallyassociated with low oxidizer mass flux and low regression rate operatingregimes.