颗粒体系在爆炸冲击流场中的界面失稳问题在灾害防控、工业安全和国防工程等领域具有广泛的应用背景。颗粒体系具有典型的多尺度结构特征，各个尺度上的力学响应相互关联。微观尺度上颗粒的变形和破碎会强烈影响细观尺度上颗粒体系的堆积结构和局部流动特性，进而影响颗粒体系界面的宏观失稳结构。另一方面，颗粒体系在爆炸波压缩(~us)和此后爆轰气体驱动的运动过程(~ms)中会经历固液相态的转变。因此，颗粒体系界面的爆炸失稳是一个极重要且兼具挑战性的多尺度多相多态问题。本项目将在对该问题合理分割时空层次的基础上，采用多尺度的实验测量和数值模拟手段，系统研究不同层次的物理过程，建立从微观到细观、从细观到宏观的关联，从微细观物理机制入手解释颗粒体系界面爆炸失稳的机理，建立宏观失稳结构与关键微细观参数的依赖关系。本项目中发展多尺度实验和计算方法可适用于研究大量涉及颗粒体系在极端条件下力学行为的问题。

The interface instability of granular medium under explosion is fundamental with regard to the hazard prevention, industrial safety, ordnance engineering and other applications. Since the granular medium is intrinsically multiscale, the dynamics in one scale influences the other. The grain-scale deformation and fracture strongly affects the mesoscale structural order and local rheology, thereby influencing the macroscale interface instability of the granular medium. Besides, the granular medium undergoes the solid-to-liquid transition during the blast compression and the ensuing processes driven by the expansion of detonation gases. Therefore, the interface instability of granular medium under explosion is a multi-scale, multi-phase and multi-state problem with great challenges. .Based on the properly distinguishing the temporal-spacial scales, we endeavor to carry out a systematic investigation into the processes occurring on different scales using the multiscale experimental and computational means, establish the correlation between the processes on microscale and mesoscale, as well as on mesoscale and macroscale, reveal the instability mechanism arisen from the micro- and meso-scale physics, finally develop the relationship between the macro-scale instability structure and the determinant micro- and meso-scale parameters. The multi-scale experimental and computational techniques developed in this project are applicable to many problems involving the behavior of granular medium in extreme conditions.