Experiments are reported on a rectangular tank in forced sway motion on a Stewart platform. The tank is fitted with a central screen which consists in a vertical plate with a central vertical opening. The width of the opening is varied so that the open-area ratio of the screen covers a range from 10 % up to 90 %. From the hydrodynamic load measurement added mass and damping coefficients are derived. These hydrodynamic coefficients are compared with numerical values from a two-dimensional numerical model, based on linearized potential flow theory, where the screen is assimilated with a porous boundary where a pressure drop occurs, related to the square of the relative traversing velocity and to the relative acceleration. Good agreement is observed between experimental and numerical values, as long as nonlinear free surface effects (wave breaking) do not come heavily into play.
In the recent past much literature has appeared on Tuned Liquid Dampers (TLDs). Readers are referred to Tait (2008), Faltinsen et al. (2011), or Crowley & Porter (2012a, 2012b) for comprehensive reviews. These TLDs, which are meant to mitigate the vibratory response of tall buildings under wind or earthquake excitation, consist in tanks partially filled with water. They have much similarity with some concepts of anti-rolling tanks.
The present paper is a follow-up of two previous papers by the same authors (Molin & Remy, 2013, 2015). In these papers a numerical model is proposed, and experiments are reported, where a rectangular tank is subjected to forced oscillations in sway and roll, with a Stewart platform. The tank is fitted with a perforated screen at mid-length and different types of openings are considered: circular holes or vertical slots. From the measured hydrodynamic loads added mass and damping coefficients are derived and compared with numerical predictions.
