黏性液滴变形过程的核梯度修正光滑粒子动力学模拟

本文提出了一种核梯度改进光滑粒子动力学(KGC-SPH)方法,模拟了黏性液滴形变自由表面问题.首先,通过模拟等温黏性液滴拉伸和旋转变形,验证了KGC-SPH法较SPH法具有较高精度和更好稳定性,且能很好地保持总角动量守恒.其次,基于非等温van der Waals模型对平衡态圆形液滴的形成过程进行数值研究,观察到小幅度振荡现象,并给出了一种新的克服张力不稳定性的方法和一种适合KGC-SPH方法的新的表面张力处理技术.最后,研究了van der Waals液滴的周期性振荡现象,讨论了初始椭圆形液滴长短半轴比 关键词： 光滑粒子动力学 黏性液滴 van der Waals模型 表面张力

The deformation process of viscous liquid drop studied by using kernel gradient corrected SPH method

In this paper, a kernel gradient corrected smoothed particle hydrodynamics (KGC-SPH) method is proposed to simulate the deformation process of a viscous liquid drop. The KGC-SPH method has higher accuracy and better stability than the SPH method, which is verified by simulating the stretching and rotating process of an isothermal viscous liquid drop, and the property of preservation of total angular momentum of the present method is also checked. And then, the formation of a stable spherical liquid drop based on van der Waals model is investigated, and a phenomenon of periodic oscillation with small amplitude is observed. Meanwhile, a new variable smoothing length is presented to remove the unstable phenomenon and a new surface tension technique is adopted in the simulation. Subsequently, the phenomenon of periodic oscillation of a van der Waals model liquid drop is simulated using KGC-SPH method, in which the influence of the elongation and Reynolds number on the amplitude and oscillation period is discussed.