Numerical investigation on the slamming loads of a truncated trimaran hull entering regular waves

For ship slamming, waves can disturb the water entry progress and thus affect the slamming load characteristics. This paper studied the slamming loads of a trimaran entering regular waves based on the CFD method. The results of a trimaran model impacting calm water and wedge impacting waves are used to verify the present method. The free surface evolution and load characteristics of the trimaran model considering wave effects are discussed. The results showed that the position at which the structure touches the wave surface depends on the formation, deformation and escape of bubble flows, which cause obvious asymmetrical flow. The enclosure of the air cavity induces a step increase in pressure, and the pressure peak appears when the bubble fully escapes. Three typical positions, wave crest, wave cross and wave through, are chosen to explore the influence of waves on slamming loads. The impact load shows a 98% difference at different wave locations. In ship load forecasting, the position of the waves relative to the hull is noteworthy. The influence of the water entry velocity on the slamming load is further discussed. Bubble retention related to the water entry velocity is the key factor affecting the peak load.