mass fraction 110 nozzle throat ratio reference numeral 2302 signifies the effect of throat area variation on ethylene mass fraction 100 nozzle throat ratio reference numeral 2303 signifies the effect of throat area variation on ethylene mass fraction 90 nozzle throat ratio and reference numeral 2304 signifies the effect of throat area variation on ethylene mass fraction 80 nozzle throat ratio fig2 illustrates the effect of nozzle throat area variation on mass averaged static pressure distribution 2400 for scramjet mode flight mach number 8 reference numeral 2401 signifies the effect of throat area variation on mass averaged static pressure distribution for the flight mach number 8 110 nozzle throat ratio reference numeral 2402 signifies the effect of throat area variation on mass averaged static pressure distribution for the flight mach number 8 100 nozzle throat ratio reference numeral 2403 signifies the effect of throat area variation on mass averaged static pressure distribution for the flight mach number 8 90 nozzle throat ratio and reference numeral 2404 signifies the effect of throat area variation on mass averaged static pressure distribution for the flight mach number 8 80 nozzle throat ratio mass averaged pressure distributions for scramjet mode flight mach number 8 illustrated in fig2 also show that as throat area is reduced the initial pressure rise increases the period of the streamline structure decreases and the mean is approximately equal to the recirculation zone pressure peak to peak amplitude is roughly the same for all cases note that for the 100 case the waveform merges smoothly with the nozzle expansion the designation a8 in fig2 refers to fig1 station 8 reference numeral 1108 the 110 case shows a slight slope discontinuity just prior to the throat station and the 80 and 90 cases show.