The study of macro continuous flow has a long history. Simultaneously, the exploration of heat and mass transfer in small systems with a particle number of several hundred or less has gained significant interest in the fields of statistical physics and nonlinear science. However, due to absence of suitable methods, the understanding of mesoscale behavior situated between the aforementioned two scenarios, which challenges the physical function of traditional continuous fluid theory and exceeds the simulation capability of microscopic molecular dynamics method, remains considerably deficient. This greatly restricts the evaluation of effects of mesoscale behavior and impedes the development of corresponding regulation techniques. To access the mesoscale behaviors, there are two ways: from large to small and from small to large. Given the necessity to interface with the prevailing macroscopic continuous modeling currently used in the mechanical engineering community, our study of mesoscale behavior begins from the side closer to the macroscopic continuum, that is from large to small. Focusing on some fundamental challenges encountered in modeling and analysis of near-continuous flows, we review the research progress of discrete Boltzmann method (DBM). The ideas and schemes of DBM in coarse-grained modeling and complex physical field analysis are introduced. The relationships, particularly the differences, between DBM and traditional fluid modeling as well as other kinetic methods are discussed. After verification and validation of the method, some applied researches including the development of various physical functions associated with discrete and non-equilibrium effects are illustrated. Future directions of DBM related studies are indicated.

宏观连续流的研究有着悠久的历史。同时，对粒子数为数百或更少的小系统中的传热传质的探索引起了统计物理和非线性科学领域的极大兴趣。然而，由于缺乏合适的方法，对介于上述两种情况之间的介尺度行为的理解仍然存在很大缺陷，这挑战了传统连续流体理论的物理功能，超出了微观分子动力学方法的模拟能力。这极大地限制了介尺度行为效应的评估，并阻碍了相应调控技术的发展。要了解介尺度行为，有两种方法：从大到小和从小到大。考虑到与机械工程界目前使用的流行宏观连续建模相结合的必要性，我们对介观行为的研究从更接近宏观连续体的一侧开始，即从大到小。针对近连续流建模和分析中遇到的一些基本挑战，我们回顾了离散玻尔兹曼方法（DBM）的研究进展。介绍了DBM在粗粒度建模和复杂物理场分析中的思想和方案。讨论了 DBM 与传统流体建模以及其他动力学方法之间的关系，特别是差异。在对该方法进行验证和验证后，阐述了一些应用研究，包括与离散和非平衡效应相关的各种物理函数的开发。指出了 DBM 相关研究的未来方向。