Design and transition characteristics of a standard model for hypersonic boundary layer transition research

Effects of wall transpiration on the supersonic boundary-layer oblique-type transition

“…However, in the first half region of transpiration, the amplification rate of mode (0,2) remains unaffected by the presence of transpiration. This suggests that transpiration does not directly affect the steady modes, and the amplified growth rates of steady mode (0,2) in the region of transpiration are mainly caused by the amplified mode (1,1). This is because the fundamental mode (1,1) functions as introducing disturbances into modes (0,2) [16].…”

“…On the one hand, the presence of viscous effects and dissipation effects can result in large near-wall gradients of temperature. On the other hand, boundary-layer transition typically causes a sharp increase in aerodynamic drag and heat flux [1][2]. To mitigate high heat loads experienced by the surface, transpiration cooling [3][4] has emerged as an active cooling technique widely applied in aerospace applications.…”

“…During the linear unstable stage of natural transition, the oblique wave of the first mode is deemed the most amplified in supersonic boundary layers (Ma<4) [13]. While the well-known Mack-mode instability is often dominant in the hypersonic regime [14], following the linear stage, nonlinear wave-wave interactions lead to complicated flow mechanisms and various types of breakdowns [15]. Among these scenarios, oblique breakdown is regarded as the most probable transition path for initiating the occurrences of boundary-layer transition in supersonic cases [16][17].…”

Noise level effect on the hypersonic boundary layer

“…The laminar-turbulent transition prediction has been one of the main factors limiting the development of hypersonic vehicles. 1–7…”

“…The laminar-turbulent transition prediction has been one of the main factors limiting the development of hypersonic vehicles. [1][2][3][4][5][6][7] The boundary layer transition is a complex nonlinear phenomenon that is strongly affected by multiple factors, including freestream disturbances, the Mach number, the Reynolds number, the angle of attack, the wall temperature, leading edge bluntness, the wall roughness, and wall catalysis. 8,9 The current prediction accuracy for the hypersonic boundary layer transition is seriously insufficient.…”