Studies of Flow Induced on a Water Surface due to the Impingement of a Drop or a Water Source

The particle image velocimetry (PIV) technique is used to study the flow induced on the surface of a salt waterbody when a drop impinges on the surface or when a source is present on the surface. The measurements show that the impingement of a fresh water drop causes a strong axisymmetric solutocapillary flow about the vertical line passing through the center of impact. The fluid directly below the center of impact rises upward, and near the surface, it moves away from the center of impact. The flow, which develops within a fraction of second after the impact, persists for several seconds. Similarly, when a fresh water source is present on a salt waterbody there is a solutocapillary flow which on the surface is away from the source and below the surface is towards the source. The solutocapillary flow is quasi-steady when the volume flow rate from the source is small in the sense that the salt concentration in the waterbody changes slowly.