高超声速数值模拟平台转捩模型的标定

Calibration of transition model for hypersonic numerical simulation platform

  • 摘要: 基于CARDC的高超声速流动数值模拟软件平台Chant-2.0,以典型低速平板转捩算例为参考,对γ-Reθ转捩模型的经验关系式进行了标定,并且对压力梯度函数进行了高马赫数修正,在高超平板和尖锥的转捩算例中进行了初步检验,计算结果表明:在高超计算平台上标定的转捩模型,较好地模拟了低速平板流动的转捩起始位置和转捩区长度,经过高马赫数修正后在高超流动转捩模拟中表现出较大的潜力。

     

    Abstract: Based on CARDC hypersonic numerical simulation platform Chant-2.0, applications of γ-Reθ model to hypersonic boundary layer transition are investigated preliminarily. The transition onset and length are predicted by solving two transport equations for turbulence intermittency factor and momentum thickness Reynolds number. Firstly, γ-Reθ transition model using local correlation functions is calibrated through four cases of low speed flat flows, and in the process freestream turbulence intensities have a wide range from low level natural transition to high level bypass transition. Then, taking account of flow properties of hypersonic boundary layer, the pressure gradient function used in the transition model's Reθt correlation is properly modified for high Mach number flows. Finally, by adopting the new model functions, hypersonic boundary layer transitions of flat and sharp cone are calculated and compared with referrence data. The simulation results indicate that the specially calibrated correlations for hypersonic platform software can accurately predict the onset and length of transition region in low speed cases, and high Mach number correction shows good performance in hypersonic simulations.

     

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