SLOSHING IN PARTIALLY FILLED LIQUID TANKS AND ITS EFFECT ON SHIP MOTIONS: NUMERICAL SIMULATIONS AND EXPERIMENTAL VERIFICATION.

To ensure the structural adequacy of ship tanks carrying liquid cargoes, it is necessary to evaluate the sloshing pressures resulting from liquid motions in conditions of partial filling. When the period of ship motions happens to excite the liquid cargo near its own natural period, violent motions of the cargo take place which induce substantial dynamic pressures on the tank walls and can also impart impact pressures on the tank walls and ceiling. These pressure loads around the tank also yield an overall force and a moment which, together with the free surface effect on the metacentric height, can alter the ship motions significantly. This paper describes a non-linear transient numerical solution of liquid cargo sloshing motions and pressures currently under development at Lloyd's Register of Shipping. The paper provides comparisons of computations against experimentally measured loads on a prismatic and on a rectangular tank. It also reports some initial computations of the coupled problem of sloshing and ship motions and compares these calculations with experiments on a products carrier ship model which incorporated partially filled tanks.