An experimental study of the flow field in a rectangular tank filled with water and forced by a speaker has been carried out by using particle image velocimetry (PIV) technique. The employed experimental apparatus is sketched in figure 1. The speaker oscillation creates a disturbed field which determines a periodically waving of the free surface on the upper part of the tank. Phase-locked measurements have been performed sampling the investigated phenomenon each 12° obtaining 30 phases. Several depths d (8cm, 6cm and 4cm), working frequencies f (1.825 Hz, 2.8 Hz, 3.4 Hz) and wave amplitudes have been tested. In particular, for a fixed depth and working frequency, the wave amplitude equal or more than 10% compared to the maximum depth of the tank is obtained varying the supply voltage V. In figures are represented the PIV measurements in the following conditions: f = 2.8Hz, V = 800mV, d = 8cm of water. The phases φ=264° - φ=336° are characterized by the formation of a vortex structure such like a synthetic jet starting from the speaker outflow. This expulsion phase causes free surface oscillation with the formation of a non-sinusoidal free surface. The non-regular behavior of the free surface is caused by the contrast between the fluid going backward from the previous phases and the new injected fluid in forward direction. During the entire expulsion phase, the vortex structure is generated and convects downstream until it reaches a distance of about x=3.5w where the vortex dissolves. Simultaneously, the free surface has a sinusoidal trend as expected because of the periodical forcing. The vortex structure gets smaller while it proceeds along the tank floor because of two main reasons: diffusion of kinetic energy and interaction with the descending free surface. This interaction stops the downstream evolution of the vortex structure which collapses under the water mass moving downward. After the vortex has dissolved, the suction phase starts and causes the downward movement of the free surface at x < 2w and x > 8w.
PIV measurements of sloshing flow in a rectangular tank induced by a sinusoidal inflow / Contino, Mattia; Greco, CARLO SALVATORE; Cardone, Gennaro. - (2016). (Intervento presentato al convegno 17th International Symposium on flow Visualization tenutosi a Gatlinburg, Tennessee, U.S.A nel June 19-22, 2016).
PIV measurements of sloshing flow in a rectangular tank induced by a sinusoidal inflow
CONTINO, MATTIA;GRECO, CARLO SALVATORE;CARDONE, GENNARO
2016
Abstract
An experimental study of the flow field in a rectangular tank filled with water and forced by a speaker has been carried out by using particle image velocimetry (PIV) technique. The employed experimental apparatus is sketched in figure 1. The speaker oscillation creates a disturbed field which determines a periodically waving of the free surface on the upper part of the tank. Phase-locked measurements have been performed sampling the investigated phenomenon each 12° obtaining 30 phases. Several depths d (8cm, 6cm and 4cm), working frequencies f (1.825 Hz, 2.8 Hz, 3.4 Hz) and wave amplitudes have been tested. In particular, for a fixed depth and working frequency, the wave amplitude equal or more than 10% compared to the maximum depth of the tank is obtained varying the supply voltage V. In figures are represented the PIV measurements in the following conditions: f = 2.8Hz, V = 800mV, d = 8cm of water. The phases φ=264° - φ=336° are characterized by the formation of a vortex structure such like a synthetic jet starting from the speaker outflow. This expulsion phase causes free surface oscillation with the formation of a non-sinusoidal free surface. The non-regular behavior of the free surface is caused by the contrast between the fluid going backward from the previous phases and the new injected fluid in forward direction. During the entire expulsion phase, the vortex structure is generated and convects downstream until it reaches a distance of about x=3.5w where the vortex dissolves. Simultaneously, the free surface has a sinusoidal trend as expected because of the periodical forcing. The vortex structure gets smaller while it proceeds along the tank floor because of two main reasons: diffusion of kinetic energy and interaction with the descending free surface. This interaction stops the downstream evolution of the vortex structure which collapses under the water mass moving downward. After the vortex has dissolved, the suction phase starts and causes the downward movement of the free surface at x < 2w and x > 8w.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
