Sloshing Pressure Distribution in the Rectangular Tank partially filled with Two-layer Fluids

Fluid sloshing motion in a liquid tank has been the subject of numerous studies in the past many years. However, lots of the previous investigations were devoted to the single fluid sloshing in containers. Recently, it was found from the industry that the density stratification may change the property of sloshing. This paper will consider the two-layer fluids sloshing pressure distribution in a rectangular liquid tank by varying the depth ratio of upper and lower fluid. A two-phase flows numerical model based on the improved volume of fluid (IVOF) method will be applied for simulating violent two-layer liquid sloshing flows and slosh induced impact pressures acting on the tank wall. Laboratory experiments will be also conducted in a shaker table driven by a wave maker to further explore the sloshing characteristics when two layers of liquids are present. The fresh water and diesel oil are adopted in the experiments. Two kinds of fluids are assumed to be immiscible in this study. The pressure distribution inside liquid tank filled with different depth ratio of two-layer fluids will be obtained near the resonant frequencies. The fast Fourier transform (FFT) analysis techniques will be used to present a spectral analysis of the time series of interfacial wave and free surface wave, which can reveal the relations between the sloshing frequency and surface sloshing mode and interface vertical displacement. These studies will be used to explore the dependencies of sloshing behavior on depth ratio and density stratification.