The 2-D velocity vector distribution can be measured by Digital Particle Image Velocimetry. By this method, the motion of the scattering particles, observed in the plane of the illuminating laser light sheet, is analyzed. For this pupose, the images of the flow must contain tracers. To improve contrast and particles visibility a special filtering technique can be applied.
In the EFD, the experiment is motivated by the needs to understand and parameterize the mixing process of crude oil which occurs during degassing of oil in large underground caverns with strategic petroleum reserve (SPR). The oil is pumped from cavern to degassing station and then returns to the cavern using a turbulent jet and the resulting flow in the cavern belongs to the family of confined jet flows, which are not well studied.