Inlet and isolator are key components of the dual-mode scramjet.They should not only provide enough airflow to the engine

but also show preferable starting characteristics and supply airflow with good quality.In this paper

finite volume method and 2nd order TVD upwind scheme were exploited with S-A turbulence model to investigate the flow field in the inlet and isolator.The influence of inlet convergent angle and inlet cowl length on the performance of inlet and isolator was analyzed.The investigation indicates that isolator tend to resist higher back pressure and provide exit airflow with better quality under conditions of high mach number and low distortion.