This paper is devoted to an unresolved model for the simulation of air invasion in immersed granular flows without interface reconstruction between the liquid and the gas. Experiments of air invading a granular bed immersed in ethanol were achieved in a Hele-Shaw cell to observe the gas invasion paths and to calibrate the numerical multiscale model. The grains movements are computed at a fine scale using the non-smooth contact dynamics method, a time-stepping method considering impenetrable grains. The fluid flow is modelled by equations averaged using the volume fraction of fluid and computed at a coarse scale with the finite element method. A phase indicator function is used to dissociate the gas and the liquid constituting the fluid and to compute the density and viscosity of the fluid at each position. It is moved using a convection equation at each time step. The fluid, solid and phase indicator function computations are validated on simple cases before being used to reproduce experiments of air invasion in immersed granular flows. The experiments are supported by simulations in two dimensions to refine the study and the understanding of the invasion dynamics at short times.

本文致力于一个未解决的模型，用于模拟浸没颗粒流中的空气入侵，而无需在液体和气体之间进行界面重建。在Hele-Shaw池中进行了空气浸入浸有乙醇的颗粒床的实验，以观察气体的入侵路径并校准数值多尺度模型。使用非光滑接触动力学方法（考虑了难以穿透的晶粒的时间步长方法），可以精细地计算晶粒的运动。通过使用流体体积分数求平均的方程对流体流动进行建模，并使用有限元方法在粗略范围内进行计算。相位指示器功能用于分解构成流体的气体和液体，并计算每个位置的流体密度和粘度。它在每个时间步使用对流方程进行移动。在用于重现浸没颗粒流中的空气入侵实验之​​前，先对简单情况下的流体，固体和相位指示剂函数计算进行验证。在二维上通过仿真来支持实验，以改进研究并在短时间内了解入侵动力学。