In order to obtain the relative optimal opening rate of the open-cut tunnel portal,the three-carriage high-speed train running through the hood with different opening ratios (20％-84％) at different speeds (250,300 and 350 km/h) was modeled by using sliding mesh method,and the three-dimensional unsteady compressible Reynolds-averaged N-S equation and standard κ-ε equation turbulence formula were employed in this numerical model.Then the initial compression wave and micro pressure wave were simulated and analyzed.The results indicate that the numerical results show a well agreement with the dynanic model test,and the deviation between them is no more than 6％.The amplitude of initial compression wave increases when the hood with holes,and it increases at first stage and then decreases with the increasing of opening ratios,and reaches the maximum value when the opening ratios is 60％.The pressure gradient of initial compression wave is significantly affected by the opening rate.It decreases with increasing of the opening rate,and the amplitude shows a small change when opening rate is greater than 40％.Similarly,the effects of opening rate micro pressure wave show the same rules as the pressure gradient.%为获得等截面开口型缓冲结构相对最优开口率,基于三维非定常可压缩雷诺时均N-S方程和标准κ-ε双方程湍流模型,采用滑移网格方法,对3车编组的高速列车分别以250、300、350 km/h速度通过开口率在20％～84％之间的等截面开口型缓冲结构进行模拟,并对隧道内初始压缩波和隧道出口气压爆波进行研究.结果表明:数值计算结果与动模型试验相比,波形吻合度较好,幅值偏差均不超过6％;开口对初始压缩波形幅值起到增大作用,并随开口增大而先增大后减小,在开口率为60％时达到最大;初始压缩波压力梯度受开口影响显著,随着开口率增大而减小,且在开口率为40％以后变化不大,气压爆波随开口率变化规律与初始压缩波压力梯度基本一致.
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