In this study, we develop an innovative numerical method for the investigation of the stability of a partially filled tank wagon moving on a curved track. The calculations are carried out in two subsystems including a dynamic system and fluid sloshing. We analyze the wagon dynamic system the multibody dynamic (MBD) model with 21 degrees of freedom (21-DOFs), which takes into account the lateral, vertical, roll, pitch, and yaw motions. The heuristic creep theory is used for the wheel–rail contact model. We adopt the fourth-order Runge–Kutta method for solving of this model. The transient fluid slosh is simulated by the computational fluid dynamic (CFD) model. The volume of fluid (VOF) technique is used for tracking the free surface of the fluid. This model is validated experimentally using the sloshing test setup. Then the simultaneous interaction between the dynamic system and the transient fluid slosh is analyzed by coupling the CFD model with the MBD model. By the parametric study on the filled-volume and wagon velocity, the critical hunting speed is derived by the Lyapunov indirect method. The results show that a higher filled volume decreases the critical hunting speed. Also, at the instability condition, an increasing trend for the phase trajectory of the wagon components is evident.

中文翻译：

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耦合CFD-MBD法分析部分装填的货车在弯曲轨道上的游动稳定性

在这项研究中，我们开发了一种创新的数值方法，用于研究在曲线轨道上移动的部分装满的货车的稳定性。计算在两个子系统中执行，包括动态系统和流体晃荡。我们分析了具有21个自由度（21-DOF）的多体动力学（MBD）模型的货车动力学系统，该模型考虑了横向，垂直，滚动，俯仰和偏航运动。启发式蠕变理论用于轮轨接触模型。我们采用四阶Runge-Kutta方法求解该模型。瞬态流体晃荡通过计算流体动力学（CFD）模型进行模拟。流体体积（VOF）技术用于跟踪流体的自由表面。使用晃荡测试设置对该模型进行了实验验证。然后，通过将CFD模型与MBD模型耦合来分析动力系统与瞬态流体晃荡之间的同时相互作用。通过对填充量和货车速度的参数研究，可以通过李雅普诺夫间接法推导临界运动速度。结果表明，较高的填充量会降低临界摆动速度。同样，在不稳定性条件下，货车部件的相位轨迹明显增加。