Dynamics of the emerging jet after drop impact

We present detailed measurements of the velocity inside the jet and in the pool below the jet after droplet impact. The motion of the emanating jet is generally considered to be ballistic, but recent findings indicate that other forces are acting on it, which causes the jet to decelerate at a much higher rate. Using combined PIV and shadowgraphy we determine the space-time diagram of the jet that emerges after drop impact. Droplets are released from heights between 100 and 1000 mm. PIV measurements provide measurements of the velocity field inside the jet. These are combined with PIV measurements of the flow in the pool below the jet. Image series are recorded at 12,800 frames per second. It is found that the deceleration of the jet tip may be up to 15 times larger than the gravitational acceleration. The results are compared against a new theoretical model that describes the dynamics of a finite-length slender jet.