 control three-dimension rough boundari layer transit superson speed control three-dimension rough boundari layer transit superson speed experi perform 12-in superson wind tunnel jet propuls laboratori california institut technolog investig three-dimension rough element sphere boundari-layer transit tain local mach number 1 90 2 71 3 67 vari trip size posit space reynold number inch indic 1 transit laminar turbul flow induc three-dimension rough element doubl row spiral vortic trail element contamin break surround field vortic 2 transit appear suddenli violent increas rough height rel boundari-layer thick 3 breakdown vortic field strength spiral vortic persist sublay ensu turbul flow 4 later space rough element initi breakdown contamin laminar flow 5 trip reynold number veloc kinemat viscos outer edg boundari layer rough height transit occur rough posit vari posit reynold number on-fourth power trip posit 