LAUSR

A one-dimensional model is proposed for transportation of a two-phase fluid (sandcontaining fluid and pure fluid) in the Hele-Shaw cell with permeable walls through which the pure fluid can leak off, causing the growth of the sand concentration. The model describes the process of pure fluid displacement with the emergence of the Saffman–Taylor instability and extends Koval’s model to the case of sand concentration variation owing to pure fluid outflow through the cell walls. The Riemann problem is analyzed. New flow configurations, which are not predicted by Koval’s model, are discovered.