Effects of wall temperature on boundary layer stability over a blunt cone at Mach 7.99

Stability characteristic of hypersonic flow over a blunt wedge under freestream pulse wave

“…The behavior of hydrodynamic stability and laminar-turbulent transition are also affected by the thermal state of the surface [5]. In the investigation on the stability of hypersonic boundary layer for the action of continuous and weak wave in freestream [14], it was confirmed that the thermal conduct mechanism of shearing flow plays an important role in determining the evolution of the disturbance wave modes and the stability of the boundary layer. Fig.…”

“…This leads to the disturbances behind the bow shock being enlarged sharply, and the disturbance waves introduced into the boundary layer being damped out [5]. After the disturbance enters the boundary layer, unstable disturbance waves with different modes are induced; the induced disturbance wave further interacts with the boundary layer and finally generates the most unstable mode dominating the transition [14]. Fig.…”

“…The greater reason for which is that disturbances move back and forth between shock and nose, and interact strongly with intensive shearing flow in the boundary layer. The disturbances behind the bow shock enter the boundary layer; one part of the disturbance wave propagates along the direction of flow, and the other repeatedly moves between shock and nose [14]. The reciprocating motion of the disturbance wave is continual for a continuous wave, while the number of motions is limited for the pulse wave due to viscous dissipation.…”

“…These mainly consider the growth and decay of normal modes in hypersonic boundary layers, and maintain that the transition is a result of exponential growth of the most unstable normal modes. This is the foundations of the N method [14]. A series of experimental and numerical studies focusing on boundary layer stability have been performed.…”

“…Most of the studies on the stability of supersonic or hypersonic boundary layers are based on adiabatic wall. However, many cases are proximately isothermal walls or between isothermal and adiabatic [14]. Some researchers have found that the wall temperature plays a critical role in determining boundary layer instability [19][20][21][22].…”