College of Mechanical Engineering, Xinjiang University, Urumqi, 830047, China.
Eur Phys J E Soft Matter. 2022 Feb 7;45(2):11. doi: 10.1140/epje/s10189-022-00168-4.
The Smoothed Particle Hydrodynamics (SPH) method is used to numerically simulate the unsteady sand ripple wind-sand flow movement in a small scale. Compared with the traditional grid-based numerical method, the SPH method uses discrete independent particles to represent the solution domain, get rid of the constraints of the computational grid, and completely solve various problems caused by large deformation or distortion of the grid based on the Euler grid method. Because it also includes the Lagrangian dynamics method, it can easily track the trajectory of any single particle, so the SPH method has unique advantages when dealing with the two-phase flow coupling of wind and sand. This paper expounds the theoretical basis and calculation method of SPH method and focuses on the design idea of applying the core factors in the SPH formula to the numerical simulation program. By discretizing the SPH numerical model of the sand ripple wind-sand two-phase flow, the temporal and spatial changes of the sand particle group on the slope surface during the wind-sand movement are simulated. The formation and development process of macro-wind-sand flow and the saltation law of micro-typical particles are analyzed, which are consistent with the existing wind tunnel experiment results, and the accuracy of SPH numerical simulation method is verified. The results show that the calculation accuracy of this method is high, and it provides a scientific theoretical basis for our further research and prevention of sand damage.
采用光滑粒子流体动力学（SPH）方法对小尺度非定常沙纹风沙流运动进行数值模拟。与传统的基于网格的数值方法相比，SPH 方法使用离散的独立粒子来表示求解域，摆脱了计算网格的约束，完全解决了基于欧拉网格方法的大变形或网格扭曲所产生的各种问题。由于它还包含拉格朗日动力学方法，因此可以轻松跟踪任何单个粒子的轨迹，因此在处理风沙两相流耦合问题时，SPH 方法具有独特的优势。本文阐述了 SPH 方法的理论基础和计算方法，重点介绍了将 SPH 公式中的核心因素应用于数值模拟程序的设计思路。通过对沙纹风沙两相流的 SPH 数值模型进行离散化，模拟了风沙运动过程中坡面沙粒群的时空变化。分析了宏观风沙流的形成和发展过程以及微观典型颗粒的跃移规律，与现有的风洞实验结果一致，验证了 SPH 数值模拟方法的准确性。结果表明，该方法计算精度高，为进一步研究和防治风沙危害提供了科学的理论依据。
