针对粒子法中表面张力计算的准确性问题，该文对连续表面力（continuum surface force，CSF）模型进行了改进。在采用一种几何法精准识别界面粒子的基础上，曲率由仅需考虑作用域内界面粒子的单位法线面散度计算得到，且表面张力仅作用于界面粒子。圆和椭圆的曲率计算结果表明，改进后的模型在合适的分辨率和光滑长度下可实现较高的曲率计算精度。采用移动粒子半隐式（moving particle semi-implicit，MPS）方法对表面张力作用下的方形液滴振荡和液滴碰撞过程进行了二维单相流动模拟，模拟结果的振荡周期与理论值接近，液滴形状合理且表面光滑，表明改进后的CSF模型可准确地模拟动态算例中的表面张力作用。
Abstract
The continuum surface force (CSF) model was used to improve the accuracy of surface tension calculation using the particle method. A geometric method was developed to accurately detect the boundary particle with the curvature calculated from the surface divergence of the unit normal, which only depends on the boundary particles in the interaction domain. The surface tension was then calculated only on the boundary particle. Curvature calculation results using a circle and an ellipse showed that the curvature calculation is more accurate with the proper resolution and smoothing length. Two-dimensional, two single-phase models of square drop oscillations and two drops colliding with surface tension effects were simulated using the moving particle semi-implicit (MPS) method. The predicted oscillation periods agreed well with analytical results with reasonable shape and smooth surfaces. The results indicate that this improved CSF model can accurately simulate the surface tension effect in two-phase flows.
关键词
粒子法 /
表面张力 /
连续表面力模型 /
移动粒子半隐式法
Key words
particle method /
surface tension /
continuum surface force model /
moving particle semi-implicit method
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参考文献
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