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• Large eddy simulation is employed to analyze the HyTRV model with upstream wall blowing/suction. • Upstream blowing accelerates the transition, while upstream suction delays the transition. • Blowing reduces skin friction while suction increases it in the controlled region. • Upstream blowing enhances the development of the streamwise vortex instability mode. To investigate the effect of wall blowing/suction on hypersonic boundary layer transition, large eddy simulation (LES) is employed to analyze the HyTRV model under an incoming flow with a Mach number of 6 and a unit Reynolds number of 10 7 m −1 . The model has a length of 1,600 mm, and wall blowing/suction is applied to the windward surface’s upstream region (450–750 mm from the leading edge). The computational results indicate that upstream blowing accelerates the destabilization and breakdown of the streamwise vortex, promotes earlier transitions in the windward vortex region, and enhances the turbulent fluctuation intensity in the outer boundary layer. Conversely, upstream suction delays the transition and suppresses turbulent fluctuations in the outer boundary layer zone. The pressure fluctuation spectra are analyzed at different streamwise positions. The results demonstrate that upstream blowing significantly amplifies the development of a disturbance wave with a frequency of approximately 33 kHz at x = 1100 mm on the windward side. This frequency is hypothesized to correspond to the streamwise vortex instability mode. In contrast, upstream suction markedly suppresses the preexisting spectral peak near 38 kHz. Spectral proper orthogonal decomposition (SPOD) is applied to the streamwise/wall-normal temperature field. The results revealed that upstream blowing substantially increases the energy contribution of the first SPOD mode at a characteristic frequency of 32.55 kHz.
Sun et al. (Wed,) studied this question.