In order to investigate the effects of factors such as Mach number, Reynolds number, sweep angle, wall temperature

and pressure gradient on the natural transition of supersonic boundary layer in the cross-flow mode and Oblique T-S mode, linear stability theory (LST) and eN transition prediction method are used in two-dimensional or quasi three-dimensional flows such as flat plates, airfoils and infinite swept-back wings. The effects of these influencing factors

on the N factor of cross-flow mode and Oblique T-S mode are studied through variable parameter analysis. Based on

the inflow and wall conditions set in the cases in this article, the calculation results show that the growth rate of the N

factor in the cross-flow mode is positively correlated with the inflow Mach number and Reynolds number, respectively. As the sweep angle increases from 30 ° to 60 °, the N factor growth of the cross-flow mode continues to accelerate. After exceeding 60 °, N factor growth in the stationary wave begins to weaken, while the N factor in travelling

wave does not change significantly in the range of 60 ° to 75°. It can be inferred that the critical sweep angle at which

the N factor in travelling wave begins to decay is larger. The N factor growth rate of Oblique T-S mode is positively

correlated with the inflow Reynolds number, the ratio of wall temperature to inflow temperature, respectively. The N

factor growth rate decreases as the inflow Mach number increases or the positive pressure gradient increases. Therefore, the influence of the variation of inflow Mach number on natural transition is related to the type of analyzed instability mode, while the trend of the influence of the variation of inflow Reynolds number on the N factor of natural

transition of cross-flow mode and Oblique T-S mode is consistent.

cross-flow mode, Oblique T-S mode, Mach number, Reynolds number, sweep angle, wall temperature