 investig separ flow pressur field investig separ flow pressur field articl describ investig type separ region blunt-base wake caviti form cutout boundari ahead dimension step superson mach number 2 4 subson flow condit exist geometri pressur field describ paper second articl publish describ investig intern flow heat transfer separ region maximum critic ratio length separ free-shear layer depth depress boundari caviti collaps leav mutual independ separ region protrus critic length chang greatli laminar-turbul transit oncom boundari layer laminar turbul flow independ mach reynold number semiempir correl predict condit flow span depress arbitrari depth propos detail pressur distribut boundari caviti turbul flow present function ratio caviti length critic length pertin similar paramet short notch impact pressur revers inner portion shear layer recompress thicken shear layer type boundari layer-free stream interact govern pressur field pressur caviti constant higher free-stream long notch shear layer bend separ curv gradual ahead recompress point floor-pressur variat pronounc recoveri pressur reattach small variat drag coeffici mach number reflect chang mechan recompress detail survei mach-number distribut blunt-bodi wake mix region throat well shear layer span cutout wall present analyz gener assumpt simpl superson-wake model reli principl steadi flow mass conserv caviti adequ caviti recompress boundari show influenc thick initi boundari layer rang 0 3 3 time notch depth geometri notch present 