Motivated by the interest in accurate simulation of dense fluid-particle flows, a resolved CFD-DEM method is developed by incorporating computational fluid dynamics and discrete element method (CFD-DEM) with the immersed boundary method (IBM). In this approach, the fluid phase is simulated by the CFD while the individual particles are analyzed by means of the DEM. The direct-forcing IBM, which satisfies the no-slip boundary condition and the divergence-free condition simultaneously, is introduced to handle the interactions between rigid boundaries and fluid with inherent ease of tracking drastically moving geometries by a set of Lagrangian points. The strongly coupled system is then achieved through the successive iterative procedure. A significant advantage of the proposed method is that the fluid phase is fully resolved around the particle phase and as a result, for dense particulate flows where the interaction effects on either phase is considerably strong, the essential influence of the wake flow on particles could be reflected truthfully. The gravity-induced sedimentations of particles are performed to demonstrate the accuracy of the presented resolved method, and the comparison with the results obtained by the conventional unresolved CFD-DEM method is also performed which reveals that the proposed method shows a superiority of the precise description of the fluid-particle interactions over the conventional method especially when the dense particulate flows are involved.

出于对精确地模拟稠密流体颗粒流动的兴趣，通过将计算流体动力学和离散元方法（CFD-DEM）与沉浸边界方法（IBM）结合起来，开发了一种可解析的CFD-DEM方法。在这种方法中，流体相通过CFD进行模拟，而单个颗粒则通过DEM进行分析。引入了直接强制IBM，它同时满足防滑边界条件和无散度条件，它被引入来处理刚性边界和流体之间的相互作用，并且固有地易于通过一组拉格朗日点来跟踪急剧移动的几何形状。然后，通过连续的迭代过程来实现强耦合系统。所提出方法的显着优点是，流体相在颗粒相周围完全溶解，因此，对于其中任一相的相互作用都非常强的致密颗粒流，尾流对颗粒的本质影响可能是如实反映。进行了重力诱导的颗粒沉降以证明所提出的解决方法的准确性，并且与通过常规未解决的CFD-DEM方法获得的结果进行了比较，这表明所提出的方法显示了精确描述的优越性特别是当涉及密集的颗粒流时，流体-颗粒之间的相互作用优于常规方法。对于在任一相上的相互作用都非常强烈的致密颗粒流，可以如实反映出尾流对颗粒的本质影响。进行了重力诱导的颗粒沉降以证明所提出的解决方法的准确性，并且与通过常规未解决的CFD-DEM方法获得的结果进行了比较，这表明所提出的方法显示了精确描述的优越性特别是当涉及密集的颗粒流时，流体-颗粒之间的相互作用优于常规方法。对于在任一相上的相互作用都非常强烈的致密颗粒流，可以如实反映出尾流对颗粒的本质影响。进行了重力诱导的颗粒沉降以证明所提出的解决方法的准确性，并且与通过常规未解决的CFD-DEM方法获得的结果进行了比较，这表明所提出的方法显示了精确描述的优越性特别是当涉及密集的颗粒流时，流体-颗粒之间的相互作用优于常规方法。