The influence of the hull representation for modelling of primary ship waves with a shallow-water equation solver

Long-period ship-generated loads have become design-relevant in many shallow and confined waterways. Numerical methods based on depth-averaged equations have conceptually proven successful to provide the ship wave parameters required for waterway management and design. Yet, the validation of these models remains challenging, due to variations in hull shapes, transient ship-motion during field data collection, and the dearth of published experimental benchmark data. The present study makes use of a new experimental data set to validate novel ship-modelling options in the shallow water equations solver REEF3D::SFLOW, using its free surface pressure extension for predicting long-period ship-generated load. The model predicts the primary wave field and the maximum return current with sufficiently low errors (MAPE) of 9.09% and 23.48%, respectively. A sensitivity study reveals that a simple slender body pressure assumption yields comparable simulation performance compared to a more complex hull-derived pressure distribution. The cross-sectional area of the respective pressure function, rather than the exact pressure function shape, is found to be decisive for the correct prediction of the design parameters primary wave height and maximum return current. Based on a systematic investigation of the ship draft to water depth relation, concise guidance on the choice of appropriate pressure functions is presented. © 2022 Elsevier Ltd