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Acta Armamentarii ›› 2023, Vol. 44 ›› Issue (7): 2041-2052.doi: 10.12382/bgxb.2022.0370

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Impact of Molecular Viscosity Variation on the Analytical Wall Function

WANG Xinguang1,2, CHEN Qi1,2, WAN Zhao2,*(), GAO Xiaocheng2, YAN Zhenguo1   

  1. 1 State Key Laboratory of Aerodynamics, Mianyang 621000, Sichuan, China
    2 Computational Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, Sichuan, China
  • Received:2022-03-23 Online:2023-07-30
  • Contact: WAN Zhao

Abstract:

Based on the characteristics of hypersonic turbulent boundary layers, such as temperature, density, and laminar viscosity, the modified analytical wall function is improved to include the alternative definition of the dimensionless wall distance using variables at the edge of the viscous sublayer and the parabolic and hyperbolic variations of viscosity coefficients in the sublayer, named as para-MAWF and hyper-MAWF, respectively. Hypersonic shock boundary layer interactions are used to verify these two wall functions, which are compared with the Lauder-Sharma k-ε using fine meshes and the modified analytical wall function (MAWF). The results show that the proposed wall functions will increase the accuracy of temperature and molecular viscosity variation in the viscous sublayer compared to results by the original MAWF. As a result, the predicted wall heat-flux aligns more closely with experimental measurements, especially in the separation region. The heat flux predicted by hyperbolic analytical wall function agrees better with the experimental value. Considering that the difference of the numerical results predicted by the two wall functions is less than 5%, the hyperbolic wall function is recommended for hypersonic flows due to its simpler formulation.

Key words: hypersonic turbulent boundary layer, hyperbolic variation, parabolic variation, nondimensional wall distance, shock wave turbulence boundary layer interaction