复杂气流场下的风成沙纹数值模拟研究

Numerical Study on Aeolian Sand Ripples under the Complex Airflow Field

在风沙流行为的数值模拟研究中,准确建立气流场本构方程和沙流场本构方程对模拟结果的可靠性至关重要。采用流体力学经典问题之一的方腔流模型分析了不同雷诺数下方腔内的流体流动情况并与相关文献中的结果对比分析,从而验证了复杂风沙流数值模拟软件的有效性和相关算法的准确性。然后,建立了考虑野外实际情况的复杂风沙流模型,分析了不同雷诺数下该模型中的气流流动行为,并将气流与沙流场进行了多相耦合数值分析,探讨了复杂气流场对风成沙纹的形成过程及其影响因素。数值分析结果表明,气流的流向和大小是导致沙纹及其形貌各异的关键因素,这也与实际沙纹及其形貌各异性比较吻合。

In the research on the numerical simulation of the wind-sand flow, it was essential for the re-liability of simulation results to establish the airflow field constitutive equation and sand flow field constitutive e-quation.In this article, to verify the accuracy of the constitutive equation of airflow field, the cavity flow models with different Reynolds number were made which is one of the most classic problems based on the fluid mechan-ics, and the results were compared with related literature, then the effectiveness of the numerical simulation soft-ware and the accuracy of the related algorithms were verified.After that, the complex sand flow models were made by considering the actual situation in the field, and the air flow behavior were analyzed under the different Reynolds number, then the numerical analysis were conducted by coupling the flow and sand flow field model, accordingly the forming process and influence factors of aeolian sand ripples field on complex flow were dis-cussed.The numerical results showed that the size and the direction of airflow was the key factor leading to the sand ripples with various morphologies, this also very consistent with the anisotropy of actual sand ripples and morphology.