Dumping Effects of Submerged Vertical Baffles and Slat Screen on Forced Sloshing Motion

A numerical model is proposed of forced sloshing with obstacles through solving the Reynolds averages Navier-Stokes equation and the standard k?epsilon turbulence model. The Volume of Fluid method is adopted for capturing the free surface flow. The transport equations are solved by the CFX (spell it out) code in a moving domain to take into account the harmonic excitation of the sloshing tank. This model is validated through a case study for non linear sloshing inside a partially filled oscillating in a two dimensional rectangular tank without baffles and at resonance condition. The numerical results and previously developed analytical solution agree very well. When the frequency of the external excitation is close to the 0.98 natural sloshing motion frequency, the free surface displacement becomes larger than the case of excitation frequency close to 1.1 sloshing natural frequency. The simulated results of sloshing motion of internal vertical baffles located at the middle of the tank show thatunder harmonic excitation and at resonance condition, the displacement amplitude decreases and the sloshing frequency increases. When the vertical baffle height equal 0.75 of the still water depth, the numerical results from this study and Liu’s (2009) match agree very well. To eliminate the beating phenomenon, a slat screen is proposed. Numerical simulation results show that when the slat screen solidity increases, the displacement amplitude will decrease and the beating phenomenon will be eliminated. When, the screen solidity equals the area of the vertical baffle, the screen is more efficient to reduce the sloshing response than the vertical baffles. This reduction is attributed to the evolution of vortex shedding near the tip baffle.