Under the same constraints

a conventional 2-Dscramjet inlet and a 3-D　sidewall compression scramjet inlet were designed by using the recently developed advanced methodology.The flow field structure and overall performance were studied comparatively and numerically at Ma=4

5

6.The results indicate that

the flow field distortion of 2-D　scramjet inlet was much weaker than that of the sidewall compression scramjet inlet.The mass capture ratio of 2-D　hypersonic inlet was more greatly affected by incoming Mach numbers than that of the sidewall compression inlet.Numerical simulation shows that

the 2-D　inlet was superior to the sidewall compression inlet at the design point

while under off-design points

especially at the starting Mach number

the performance of the sidewall compression inlet was obviously superior to the two-dimensional inlet.Under the equivalent compression state

the drag characteristic of the sidewall compression inlet was superior to that of the two-dimensional inlet

while the lift force of the 2-D　dimensional inlet was greater than that of the sidewall compression inlet.