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采用有限元任意拉格朗日-欧拉（ALE）法对方形颗粒在黏弹性流体中的沉降特性进行研究。通过直接数值模拟得到了不同弹性数下方形颗粒的稳定取向角的变化情况,并讨论了颗粒长宽比和通道宽度对其沉降特性的影响。结果表明,当方形颗粒在黏弹性流体中沉降时,弹性数存在一个临界值。当弹性数小于临界值时,颗粒的稳定取向为长轴方向垂直于重力方向;当弹性数大于临界值时,颗粒的稳定取向为长轴方向平行于重力方向。颗粒长宽比和通道宽度对其沉降特性都有一定的影响。长宽比大的颗粒在沉降过程中的取向角和横向漂移的振幅更大。弹性数的临界值随着长宽比的增大而减小,随着阻塞比的增大而增大。

The sedimentation of a rectangular particle in a two-dimensional channel filled with viscoelastic fluid was simulated by using finite element arbitrary Lagrangian-Eulerian domain method. The stable orientation of a rectangular particle for different elasticity numbers was obtained,and the effects of aspect ratio and blockage ratio on the settling characters were also discussed.Results show that there is a critical elasticity number when a rectangular particle falls in a viscoelastic fluid.When the elasticity number is smaller than critical,the stable orientation is that the long side of the particle perpeiidicvdar to gravity.For larger elasticity number,the stable orientation is that the long side of the particle parallel to gravity.Aspect ratio and blockage ratio have some effects on the particle＇s settling behavior.Both the fluctuations of the orientation and lateral drifting distance increase with increasing aspect ratio.The critical elasticity number is a decreasing function of aspect ratio,and is an increasing function of blockage ratio.