 investig two-dimension superson base pressur investig two-dimension superson base pressur investig base pressur wedg mach number 2 3 laminar transit regim report temperatur veloc travers mix zone exploratori investig wake vortex hot wire flow-visual techniqu describ laminar two-dimension base pressur agre well chapman's theoret predict shear layer exhibit gross veloc distribut characterist free jet mix zone disturb origin expans-turn oncom boundari layer interest trail vortex observ explain term nonuniform mix rate wake 