A new method of artificial boundary layer transition for hypersonic inlet

In order to ensure the robustness of the scramjet propulsion system,the boundary layer approaching the hypersonic inlet should be turbulent.To develop boundary layer strips for the hypersonic vehicle,a new promising strip configuration with low drag and high efficiency was designed based on the theory of two dimensional hypersonic boundary layer transition and was tested in FD-07 wind tunnel.Whether the inlet is started or not can reflect the boundary layer/shock interaction.The pressure distribution of inlet symmetry planes and shock schlieren will be distinctively deferent for laminar and turbulent on the effect of incident shock,so pressure distri-bution of inlet symmetrical and shock schlieren were used to identify the inlet starting or not and the situation of boundary layer transition can be judged by inlet starting.The tests were conduc-ted including natural transition and artificial transition.The test results show that the boundary layer can be transited successfully using the same strip under the condition of Ma= 5 and 6 ,α=0°,and thus verifies the applicability of the strip which is designed based on the Linear Steady Theory in a wide range of Mach numbers.