Experimental Characterization of Air-Entrainment in a Plunging Water Jet System Using Particle Image Velocimetry (PIV)

This paper presents a detailed experimental study of a plunging jet on a free liquid surface. An experimental characterization facility is designed and constructed for generating a vertical round water jet impinging on a free surface of a pool. The experimental analysis focuses on the jet penetration depth, its relation to impact velocity V_j and free jet length L_j. Present results are compared with previous studies. The flowmap for four different regimes, in terms of impact jet velocity is obtained. The details of the two-dimensional velocity field below the pool liquid free surface under a no-entrainment regime, is obtained using Particle Image Velocimetry (PIV) and reveals the entrainment behavior of the impinging jet flow below the interface.