 experi boundari layer transit superson speed experi boundari layer transit superson speed test conduct 12-in continu superson wind tunnel jet propuls laboratori california institut technolog determin effect surfac cool boundari-layer transit superson speed effect cool investig test mach number 1 97 smooth cone presenc three level suppli-stream turbul 0 4 2 9 cent singl-element rough fix axial locat transit data optic magnifi-schlieren system rang mach number investig indic 1 transit smooth cone definit delai surfac cool 2 transit promot suppli-stream turbul surfac rough delai surfac cool depend degre turbul rel rough 3 advers effect increas turbul rough decreas increas mach number 