Morphological stability of an interface between two non-Newtonian fluids moving in a Hele-Shaw cell.

The problem of the morphological stability of an interface in the case of the displacement of one non-Newtonian fluid by another non-Newtonian fluid in a radial Hele-Shaw cell has been considered. Both fluids have been described by the two-parameter Ostwald-de Waele power-law model. The nonzero viscosity of the displacing fluid has been taken into account.

Experimental investigation of the onset of instability in a radial Hele-Shaw cell.

The initial stage of interface instability upon radial displacement of a fluid in a Hele-Shaw cell is investigated. An air-silicone oil system is analyzed. The critical radii of stability relative to long-wave perturbations are determined.

Entropy production and stability during radial displacement of fluid in Hele-Shaw cell.

The entropy production in the problem of the radial displacement of a fluid in the Hele-Shaw cell is determined. The morphological stability of the interface between the displaced and displacing fluids is studied using the linear analysis for stability and the maximum entropy production principle. Regions, in which different forms of the interface can coexist, are predicted.