基于RANS/NLAS的火箭跨声速脉动压力环境预示

摘要

为了快速准确地预示大型火箭结构的脉动压力环境,采用雷诺平均N-S方程(RANS)求解流场、非线性噪声求解方程(NLAS)求解声场相结合的技术途径,数值求解了跨声速阶段火箭表面锥柱肩部、船尾倒锥、裙柱部区典型位置处脉动压力,给出了火箭在不同马赫教条件下的均方根脉动压力系数、声压级等.结果表明,基于RANS/NLAS方法,并应用两方程非线性k-ε湍流模型、远场吸收边界及壁面函数法,可成功地进行火箭跨声速脉动压力环境的预示；船尾倒锥区的脉动压力环境较锥柱肩部、裙柱部区更为严重,且马赫数为0.9 ～0.975时,船尾倒锥区的脉动压力环境最为严重；脉动压力能量主要集中在低频(100 Hz附近).%In order to predict the fluctuating-pressure conditions with large-scale rocket rapidly and accurately, a combined approach with the Reynolds-averaged Navier Stokes ( RANS) solved for flow field and the Non-linear Acoustics Solver ( NLAS) for acoustical field was applied.The numerical solutions of the fluctuating pressures typically at cone-cylinder shoulder、 stem inverted cone,skirt-cylinder shoulder of rocket in transonic flow were shown,and the root-mean-square fluctuating pressure coefficients and sound pressure levels with various mach numbers were given. The results indicate that the RANS/NLAS method combined with twoequation non-linear κ-ε turbulence model, far-field absorbing boundary condition and wall function can be successfully used in solving fluctuating pressure conditions with a transonic rocket; the fluctuating pressure at inverted cone is more serious than those at cone-cylinder and skirt-cylinder,and at inverted cone is the most serions fluctuation pressure encountered in flow with Mach number from 0.9 to 0.975; the energy of fluctuating pressure is almost in low frequency( about 100 Hz ).