Numerical study on sloshing characteristics and impact pressure suppression in a tank

Abstract

The study on sloshing characteristics in a rectangular or prismatic tank are approached numerically. To ensure reliability of numerical results using RANS equation with VOF model, the numerical results are compared with potential theory under small amplitude excitation. Also, a comparative study is conducted for verification using experimental results quantitatively and qualitatively for the violent sloshing phenomena which has strong nonlinearity. Basically, a sloshing load analysis in DNV guideline is employed to the research method. In a part of the study on sloshing impact pressure suppression, using air trapping mechanism which is obtained by sloshing flow between horizontal baffle arrays is used and a maximum of 63.6% reduction of sloshing impact pressure is observed. In the study of the influence of the tank shape and its natural frequency, which are not reflected in the present guideline, the bottom chamfered shape of prismatic tank is used as parameter, and the results are compared with cases using the correlation of the natural frequencies of prismatic shapes and the natural frequency of rectangular tank case. In addition, in the part of the upper part shape effects, the sloshing wave behavior changes are reported due to the roof angle variation, and the results are analyzed using pressure values obtained at specific points. High Reynolds numbers are used as parameter of tank excitation to analyze the sloshing characteristics and sloshing pressure shapes. Also, rectangular and prismatic shapes are used, and it can be seen that the limit of theoretical application, and variation of the sloshing pressure formation. In order to analyze the frequency components of excitation force, the Fast Fourier Transform (FFT) technique is adopted. The results show that the influence of the frequencies of integral multiples of the excitation frequency dominantly appears when resonance occurred.

The study on sloshing characteristics in a rectangular or prismatic tank are approached numerically. To ensure reliability of numerical results using RANS equation with VOF model, the numerical results are compared with potential theory under small amplitude excitation. Also, a comparative study is conducted for verification using experimental results quantitatively and qualitatively for the violent sloshing phenomena which has strong nonlinearity. Basically, a sloshing load analysis in DNV guideline is employed to the research method. In a part of the study on sloshing impact pressure suppression, using air trapping mechanism which is obtained by sloshing flow between horizontal baffle arrays is used and a maximum of 63.6% reduction of sloshing impact pressure is observed. In the study of the influence of the tank shape and its natural frequency, which are not reflected in the present guideline, the bottom chamfered shape of prismatic tank is used as parameter, and the results are compared with cases using the correlation of the natural frequencies of prismatic shapes and the natural frequency of rectangular tank case. In addition, in the part of the upper part shape effects, the sloshing wave behavior changes are reported due to the roof angle variation, and the results are analyzed using pressure values obtained at specific points. High Reynolds numbers are used as parameter of tank excitation to analyze the sloshing characteristics and sloshing pressure shapes. Also, rectangular and prismatic shapes are used, and it can be seen that the limit of theoretical application, and variation of the sloshing pressure formation. In order to analyze the frequency components of excitation force, the Fast Fourier Transform (FFT) technique is adopted. The results show that the influence of the frequencies of integral multiples of the excitation frequency dominantly appears when resonance occurred.