Interface stability of compressible fluids in porous media

The stability of flows in porous media plays a vital role in transiting energy supply from natural gas to hydrogen, especially for estimating the usability of existing underground gas storage infrastructures. Due to mixed gases inside storage, the interface stability of tangential-velocity discontinuity provides us the exact velocity rate in injecting and withdrawing natural gases effectively. Thus, this research aims to analyze the interface stability of the tangential-velocity discontinuity between two compressible gases by using Darcy's model to include the porosity effect. The results shown in this research will be a basis for considering whether underground gas storage in porous material can store hydrogen. We show the relation between the Mach number M, the viscosity μ, and the porosity e on the stability of the interface. This interface stability affects gases' withdrawal and injection processes, thus will help us to determine the velocity with which gas can be extracted and injected into the storage effectively. By imposing solid walls along the flow direction, the critical values of these parameters regarding the stability of the interface are smaller than when considering no walls. The consideration of bounded flows approaches the problem more realistically. In particular, this analysis plays a vital role when considering two-dimensional gas flows in storages and pipes.