Experimental study of sloshing flows in a rectangular tank under coupled pitch and heave excitations

Sloshing in partially filled containers under external forces has significant implications across industries like aerospace and oil and gas transportation. The present study aims to explore the influence of the first and second order Faraday waves on both resonant and non-resonant pitch sloshing, as well as the effects of coupled resonance. Laboratory experiments were conducted to analyze sloshing impact pressures and record wave elevations, delving into how Faraday waves alter wave shapes and impact pressure dynamics, especially in shallow water conditions. Key findings reveal significant effects of Faraday waves on both resonant and off-resonant pitch excitation. In shallow water, the presence of the first mode Faraday wave leads to reduced pressure through upward-deflected breaking impact waves, while the second mode Faraday wave intensifies impact pressure by generating flip-through waves carrying substantial energy before impacting the sidewall. Furthermore, the study explores the interaction between pitch and heave excitations, revealing how combined resonance affects sloshing behavior. Coupled-resonant sloshing waves induce periodic pressure behavior due to energy dissipations, providing insights into the complex dynamics of sloshing flows under various excitations, crucial for optimizing design and ensuring safety in engineering applications.