Predicting wave-induced loads on a moored ship with a non-hydrostatic wave-flow model

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Dirk Rijnsdorp, Marcel Zijlema, Julie Pietrzak

Tuesday 30 june 2015

17:42 - 17:45h at Europe 1 & 2 (level 0)

Themes: (T) Water engineering, (ST) Computational methods, Poster pitches

Parallel session: Poster pitches: 7E. Engineering - Computional

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Traditionally, ships are moored at jetties located inside a sheltered area (such as a harbour), which reduces wave impacts and allows for safe operations. With the recent increase of ship dimensions, entrance channels are deepened and widened, and jetties are located closer to the harbour entrance. Besides, there is an increasing demand for the construction of marine jetties at exposed locations, especially for the Liquefied Natural Gas industry. These developments lead to a greater exposure of moored ships, and puts stringent demands on the design of the jetties and mooring systems. This makes an accurate prediction of the wave-induced response of a ship, moored in a harbour or coastal region, of vital importance to ensure safe operations (e.g. loading and offloading activities). Several studies have used a model train to predict the wave-induced loads and motions of a moored ship (e.g., Bingham 2000, van der Molen and Wenneker, 2008, Dobrochinski 2014). Such a model train combines a wave-resolving model, which accounts for the wave propagation inside the domain (excluding the presence of a ship), with a diffraction model that computes the wave-induced forces on the ship. The overall aim of this study is to develop a single numerical model tool, to predict the wave-induced response of ship that is moored in a harbour or coastal region. For this purpose, the open-source non-hydrostatic wave-flow model SWASH (Simulating WAves till SHore, Zijlema et al., 2011) will be extended by nesting a floating body. In this work, we will present the numerical framework and validate the proposed method. The capabilities of the model will be assessed for the prediction of wave-induced loads on a restrained ship, that is located in open water and in a harbour basin. Model predictions will be compared with results of a physical model experiment (WL|Delft Hydraulics report, 2004), that was conducted in the Vinjé basin at Delft Hydraulics (now Deltares). References Bingham, H.B. (2000), Coastal Engineering 40, 21–38. Dobrochinski, J.P.H. (2014), M. S. thesis, Delft University of Technology, Delft, Netherlands. van der Molen, W., Wenneker, I. (2008), Coastal Engineering 55, 409-422. WL|Delft Hydraulics report, (2004), Delft, The Netherlands. Zijlema M., Stelling G.S., Smit P.B., (2011), Coastal Engineering, 58, 992-1012.