Hypersonic boundary-layer transition prediction technique plays a critical role in the aerodynamic and thermal protection design of supersonic/hypersonic vehicles. To enhance the Mach number applicability of transition prediction models and meet modern aircraft design requirements for multicondition and high-precision predictions, this study improves the calculation methods of key variables required for constructing the Mack second-mode timescale in the transition-turbulence prediction model proposed by Qiao, L., Xu, J., Bai, J., and Zhang, Y. “Fully local transition closure model for hypersonic boundary layers considering crossflow effects,” AIAA Journal, Vol. 59, No. 5, 2021, pp. 1692-1706. https://doi.org/10.2514/1.J059765 . Specifically, temperature correction was implemented for momentum thickness calculation to better reflect the overall flow characteristics of boundary layers. The correlation between boundary-layer thickness and momentum thickness was recalibrated by comprehensively considering Mach number effects and temperature effects under different wall conditions (adiabatic walls and cooled/heated walls). Additionally, inflow disturbance effects were incorporated to improve model adaptability to various experimental environments. After the model modification, validations were conducted through several wind-tunnel test configurations under various Mach numbers, Reynolds numbers, and wall temperature conditions. Results demonstrate that, compared with previous studies, the improved model performs well in transition prediction across a wider Mach number range, effectively validating the rationality and accuracy of the proposed modifications. This advancement establishes a more extensive application foundation for the overall aerodynamic design, thermal protection structure design, and flight stability evaluation of hypersonic vehicles.
Zheng et al. (2025) studied this question.