Evaluation of sloshing wave crest impact pressure acting on a fixed roof cylindrical tank

This report describes the applicability of a newly developed computer code SLOSH-3D on estimating of sloshing wave crest impact pressure acting on a fixed roof of cylindrical tank. Based on the computed results, slosh-induced pressure loads and distribution on the tank roof is presented. A large shaking table test conducted on the E-Defense shaking table by a joint study group, composed of some electric companies, has been analyzed. In the shaking table test, partially water-filled cylindrical tank (diameter: 3m, height: 3m, water depth: 2.3m or 1.9m) with a flat fixed roof was subjected to a sinusoidal excitation at the first sloshing resonant frequency. The computer code well simulated the observed waveform with a spiky rising large pressure at the time of liquid impact on the tank wall, including appearance of negative pressures in the post impact period, with sufficient accuracy. As for the liquid impact zone of the tank roof including the water splash phenomena, the numerical computations indicated good agreement with the observed results. Furthermore, the numerical computations provided the total pressure load and pressure distribution on the tank wall at an instant of time when maximum pressure peak occurs. Consequently, the computer code SLOSH-3D was capable of predicting the complex nonlinear sloshing behavior with the collision of the liquid surface against the thank roof with an acceptable level of accuracy. (author)