基于SPH模型的2种压力振荡抑制算法比较分析

A comparative analysis on the effect of two SPH schemes on suppressing pressure oscillation

  • 摘要:
      目的  传统光滑粒子流体动力学(SPH)方法在模拟包含自由液面的水动力学问题时存在流场压力振荡。为了选取有效的算法来抑制压力振荡,对比分析密度正则化和密度耗散项这2种密度耗散算法对压力振荡的抑制效果。
      方法  采用波高探测程序定量比较流动形态,并考虑运动速度对2种算法的影响。针对二维矩形液舱中的晃荡问题,考虑在不同的角速度情况下,选取流场中的压力和波面高度变化综合评判2种算法的效果。
      结果  通过比较后发现,密度耗散项算法在耗散系数取为0.05时在不同的角速度情况下,均能有效抑制压力振荡,获得更稳定的流场压力和波面形态;当角速度较小时,密度正则化算法的结果较差。在角速度高的晃荡问题中,2种SPH算法对抑制压力振荡的效果基本持平。
      结论  该结论具有一定的工程借鉴价值。

     

    Abstract:
      Objectives  With the traditional smoothed particle hydrodynamics method, there is pressure oscillation in the flow field when simulating hydrodynamic problems involving free surfaces. In order to find out an effective algorithm to suppress pressure oscillation, the effects of two density diffusive algorithms, consisting of density re-normalization and density dissipation on suppressing pressure oscillation, are compared.
      Methods  In this paper, a program to quantitatively measure wave elevation was employed and the effects of motion speed on these two algorithms were considered. The sloshing problems were simulated by using these two algorithms, respectively, and the pressure of one point within the fluid field and the wave elevation of the free surface were plotted at different angular velocities.
      Results  By comparing the results obtained by the two algorithms, it was found that algorithms with a diffusive term when the coefficient is 0.05 can effectively suppress the pressure oscillation and obtain a more stable pressure and smoother free surface profile at different angular velocities. At a lower angular velocity, the density re-normalization algorithm does not express very well. At a higher angular velocity, both the two algorithms express very well, and suppress the pressure oscillation.
      Conclusions  This conclusion makes a considerable contribution to engineering。

     

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