In order to predict the transition position using eN method for flat boundary layer with concave groove

the effects of concave groove on the evolution of disturbance in supersonic boundary layer with Mach number of 4.5 were studied by numerical simulation and flow stability method. The amplitude and growth rate distribution along the flow direction with two sizes of concave groove was revealed. The results show that the range of effect of concave groove on the basic flow is only limited in the concave groove and near range. Concave groove has a suppressed effect on the evolution of disturbance to some extent

the bigger size means the more obvious inhibitory effect. After concave groove

the effect of concave groove on the growth rate of disturbance amplitude is little

and relative variation is smaller than 2%.At the same time

the position of transition can be predicted more accurately with a smaller concave groove by eN method combined with stability analysis and a correction factor of N.