Receptivity of Mack modes to localized unsteady blowing and suction in a chemical non-equilibrium hypersonic boundary layer

• Published in: Acta mechanica Sinica Vol. 40; no. 7
• Main Authors: Yuan, Qingjiang, Song, Runjie, Dong, Ming
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences 01.07.2024; Springer Nature B.V
• Edition: English ed.
• Subjects: Base flow; Blowing; Boundary layer transition; Classical and Continuum Physics; Computational Intelligence; Engineering; Engineering Fluid Dynamics; Enthalpy; Frequencies; Hypersonic boundary layer; Ideal gas; Perturbation; Research Paper; Suction; Theoretical and Applied Mechanics; Transition to turbulence; Chemical non-equilibrium flow; Hypersonic; Receptivity; Boundary-layer instability
• ISSN: 0567-7718; 1614-3116
• DOI: 10.1007/s10409-023-23485-x

This paper studies the local receptivity of the Mack-mode instability to localized unsteady blowing and suction (UBS) in a chemical non-equilibrium (CNE) hypersonic boundary layer. The five-species CNE model is employed, and the receptivity efficiency is formulated by use of the residual theorem. Compared with the results for the calorically perfect gas (CPG) model, we find that the real-gas effect enhances the receptivity efficiency remarkably in the majority of the second-mode frequency band, and the enhancement is mainly attributed to the modification of the base flow due to the CNE effect, which is akin to the cold-wall effect in hypersonic boundary layers. Combined with the destabilizing role of the CNE effect on the Mack second mode, it is concluded that the CNE effect would lead to a greater linearly accumulated perturbation amplitude, implying premature of transition to turbulence in a high-enthalpy hypersonic boundary layer subject to localized perturbations.