The Air-Water Sloshing Problem: Parametric Studies on Excitation Magnitude and Frequency

Abstract

The problem of liquid sloshing has gained recent attention with the proliferation of liquefied natural gas (LNG) transport in partially filled tanks of a tanker vessel. In this paper, we first present the rudiments of a linear potential theory for sloshing motions in a two-dimensional rectangular tank due to small amplitude sway motions. We obtain closed form solutions for the Response Amplitude Operator (RAO) of slosh amplitude as a function of frequency. Then we present the computational fluid dynamics (CFD) formulation of the problem using dynamic meshing features. The CFD results for RAO are compared with theory, and good agreement is noticed. The impact pressure time series is compared with published experimental data, and good agreement is seen. Contrary to common observations, we notice that turbulent flow models give better and more accurate results than laminar models. CFD simulations are then performed for a range of excitation amplitudes and frequencies. Pressure contours and water surface elevation are monitored as function of excitation amplitude and frequency, and the regions of impacting vs. non-impacting are delineated.