Resonant sloshing in a rectangular tank under coupled heave and surge excitations

Abstract

This paper investigates the resonant sloshing excited by coupled surge and heave excitations. A rectangular tank with a width-to-length ratio of W/L = 1/2 and an intermediate liquid depth of h/L = 0.2 are considered. Through laboratory experiments and numerical simulations, the nonlinear characteristics of the sloshing wave and dynamic pressure are investigated, and their correlations with the external excitation frequency are explored. It is found that when the sum or difference of the surge and heave frequencies approach to the system's odd-number-order natural frequencies, the resonant sloshing occurs even though neither the surge nor the heave excitation triggers resonance by itself. Nevertheless, the most violent sloshing happens when both heave and surge excitations locate in their corresponding resonant regions. The excitation frequency that induces the maximal resonance is slightly larger than that of the analytical value due to the effect of wave nonlinearity. The rising time and impact pressure during slamming under different excitation conditions are also analysed and discussed.