Hypersonic vehicles have the benefit of rapid global arrival, high detection difficulty, strong penetration ability, and high combat effectiveness, and therefore become one of the main focuses of international competition. A number of hypersonic flight verification projects have been successfully carried out, but there are still many unknown areas. Boundary layer (BL) transition is one of the most important and inevitable uncertainties (Bertin and Cummings in Prog Aerosp Sci 39:511–536, 2003; An Fuxing, Li Lei, SU Wei, Liu Wenling and Dong Chao. Key issues in hypersonic vehicle aerodynamic design. SCIENTIA SINICA Physica, Mechanica & Astronomica, 2021, 51(10):6–25. (in Chinese);). Within the flight altitude, speed, and Reynolds number range of hypersonic vehicles, the BL transition has a high probability of occurrence (Bertin and Cummings in Annu Rev Fluid Mech 38:129–157, 2006). As shown in, vehicles powered by air-breathing propulsion systems spend most of their atmospheric hypersonic flight in conditions where the flow will be transitional. In a higher attitude with faster speed, the BL transition becomes more complex because of the interaction with real-gas effects. Particularly, it might occure under other flight conditions where the flow around the vehicles is normally thought to be laminar unless roughnesses or defects exist.