Understanding of local behavior of sloshing pressure is essential for design of LNG containment systems, particularly for operations in offshore environments. Extensive sloshing experiments revealed that local pressures at temporal resolution on the order of 20 kHz and spatial resolution of 5mm for scaled models up to 1:20 are stochastic; peak pressure varies dramatically from cycle to cycle even under a simple harmonic excitation in one degree of freedom. In addition, such pressures are strong functions of local geometry such as corrugations and raised invar edges, as well as physical and thermal conditions of the ullage. As such, the phenomenon is very challenging for predictions using existing numerical algorithms. To obtain proper design values for the containment system, scaled model tests must address the above parameters and appropriate scaling laws identified. In this paper, we assimilate fundamental aspects of sloshing from first principles to identify relevant dimensionless numbers necessary for dynamic similarity of scaled model tests involving local pressures. Various experiments were carried out to support relevance of such dimensionless numbers; experimental results and their implication in scaling will be discussed in the paper.
Impulsive loads that resulted from body entry into fluids had been extensively studied from the turn of the 20th century. von Kármán (1929) and Wagner (1932) employed potential flow theory to study the 2-D cylinder and wedge entry problem respectively by neglecting the effects of gravity (fluid acceleration during impact are much larger than that of gravity). The potential function was assumed to be φ = 0 at the mean free surface z = 0. This condition was subsequently relaxed by many investigators, noticeably that of Zhao and Faltinsen (1993) and Zhang, Yue and Tanizawa (1996). Solutions obtained from these techniques are deterministic, i.e. the same initial and boundary conditions always lead to the same solutions.
