Stabilization of viscous fingering in a partially miscible system

Viscous fingering (VF) or Saffman-Taylor instability occurs when a less viscous fluid displaces a more viscous one in porous media or in Hele-Shaw cells. The classical VF can be divided into two; miscible and immiscible systems depending on whether two fluids are miscible or immiscible. In addition, it has been recently reported that a partially miscible VF has experimentally shown to change to multiple droplets pattern. However, in the present study, we have experimentally shown a partially miscible VF can have the potential to stabilize the interface more effectively, namely, leading to circular-like pattern in a radial geometry. This is considered to be caused by the two factors; a convection induced by spinodal decomposition directed from the more viscous fluid to the less viscous one and a high rate of the spinodal decomposition.