Fig. 4

Damping ratios \( \kappa \) of the free sloshing oscillation in the 1st axial and circumferential mode for a broad tank with slenderness \( \alpha_{L} = 0.3 \), a kinematical viscosity \( \nu_{L} = 4.2 \times 10^{ - 4} {\,\text{m}}^{ 2} / {\text{s}} \) and a density \( \rho_{L} = 912\;{\text{kg/m}}^{ 3} \) (oil, SAE 30 at 15.6 °C) in dependence of the tank radius R. The damping is size dependent and decays with increasing tank volume. Furthermore the liquid motion at the tank bottom dominates the damping