Experimental Investigation of the Influence of Short-Crested Seas and Swell on Sloshing-Induced Impact Loads

The assessment of the structural strength of liquefied natural gas membrane tanks onboard ships requires the investigation of the sloshing-induced impact loads. Those loads are usually determined via model tests usually neglecting the influence of swell. In the present study, we experimentally investigated sloshing-induced loads resulting from ship motions in long- and short-crested pure wind seas and combinations of wind sea and swell. Impact loads and counts were correlated with wave spreading functions, tank filling levels, and tank natural sloshing frequencies. Results emphasized that short-crested seas increased impact loads for highly filled tanks. Furthermore, swell had a significant influence on sloshing-induced impact loads.