【摘要】 为准确计算渤海海冰的动力过程,本文将质点网格方法(Particle in cell,简称PIC),引入到渤海海冰数值模拟中。该方法首先在欧拉坐标系下对海冰动力方程和连续方程进行差分求解,并插值出各网格内海冰质点的速度和密集度,然后在拉格朗日坐标系下对海冰质点的位移和各网格的平均冰厚进行确定。PIC方法将欧拉法与拉格朗日法相结合,避免了欧拉坐标下有限差分法的数值扩散和拉格朗日坐标下光滑质点流体动力学计算量大的缺点。在对渤海海冰动力过程的数值模拟中采用了Hibler的粘塑性本构模型,并考虑了海冰热力作用过程。利用PIC方法对辽东湾海冰进行了48h数值模拟,结果表明:该方法可成功地处理海冰流变过程,精确计算出冰缘线位置和海冰分布状况,对海冰厚度和密集度的计算精度均优于有限差分法。PIC方法在精确模拟海冰的重叠和堆积过程,以及为冰区油气作业提供详实的海冰信息方面都有良好的应用前景。更多还原

【Abstract】 Particleincell (PIC) approach was introduced into the sea ice numerical simulation of Bohai Sea. In the PIC approach for sea ice dynamics, the momentum and continuity equations are calculated with Finite Difference method (FDM) to determine the ice velocitits and concentration of Eularian cells, then the velocity and concentration of Lagrangian ice particles are interpolated from the cells above with a bilinear interpolating function. With the movement of particles, the ice thickness of Eularian cells can be adjusted based on the new location of ice particles. For the coupling of Eularian and Lagrangian coordinates in PIC approach, the numerical diffusion in Eulerian FDM and the excessive computation in Lagrangian Smoothed Particle Hydrodynamics (SPH) were both avoided. In the present sea ice dynamics simulation of Bohai Sea, Hibler’s viscousplastic constitutive law was adopted. Considering sea ice thermodynamics, the simulated ice thickness and concentration with PIC compared better with the satellite remote images than that of FDM. The PIC approach can also be applied to simulate the ice ridging and rafting processes precisely, and also to supply more reliable ice information for offshore oil/gas exploitation.更多还原