The study of the nonlinear evolution of three-dimensional disturbances in the boundary layers has a great theoretical research significance to the hydrodynamic stability.PSE method is adopted to study the subharmonic resonance in the experiment,and comparison be-tween PSE results and experimental data is presented.The numerical results by PSE match the experiment results basically in quantitatively.In the qualitative comparison,the plane wave ex-periences a linear exponential growth in the beginning stage and parametric-resonance stage,and the subharmonic oblique waves also experience a linear exponential growth in the initial stage. However,when the nonlinear effects is relatively strong,the subharmonic oblique waves experi-ence a super exponential growth that is faster than the exponential growth predicted by the linear theory,and stmulate the plane wave to make it increase again.This result is a consistent with the theoretical description.%用抛物化稳定性方程（PSE）方法数值模拟了实验中三波共振中三维扰动的非线性作用情况，得到的计算结果与实验数据在定量上比较相符。研究表明扰动演化的定性行为与理论描述的结果是一致的，即二维波在初始阶段和参数共振阶段按照线性指数增长，三维波在初始阶段同样按照线性指数增长。在非线性作用比较强时，三维波快速增长起来，最终作用在二维波上，使其再次增长起来，从而引起转捩。
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