The falling stream creates a dimple in the oil bath. The oil jet slides on a layer of air and then ramps out of the dimple. Under certain conditions, this phenomenon will occur twice as seen in the above photo.
Oil is slick but did you know it can also bounce? Physicists at the University of Texas at Austin Center for Nonlinear Dynamics poured a stream of oil into a rotating container of oil. Instead of just mixing with the rest of the oil in the container, the stream gradually pulled up and jetted into the air. The researchers found that the stream of oil carried a thin layer of air with it into the moving oil bath. The jet glided along the thin layer of air and ramped into the air.