URANS predictions of wave induced loads and motions on ships in regular head and oblique waves at zero forward speed

• Published in: Journal of fluids and structures Vol. 74; pp. 178 - 204
• Main Authors: Jin, Yuting, Chai, Shuhong, Duffy, Jonathan, Chin, Christopher, Bose, Neil
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2017
• Subjects: FLNG and LNG; Transfer functions; Unsteady Reynolds-averaged Navier–Stokes; Wave induced loads and motions; Zero forward speed; FLNG and LNG; Zero forward speed; Unsteady Reynolds-averaged Navier–Stokes; Wave induced loads and motions; Transfer functions
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1016/j.jfluidstructs.2017.07.009

The paper presents predictions on the hydrodynamics of a conceptual floating liquefied natural gas (FLNG) and a liquefied natural gas (LNG) carrier in regular head and oblique sea waves using an unsteady Reynolds-Averaged Navier–Stokes (URANS) solver. Initially, a verification and validation study is performed on estimating the numerical uncertainties in the presented URANS simulations. Using the verified numerical setup, ship hydrodynamic properties including wave induced loads as well as ship motion responses are investigated for different wave conditions. The computed time history results are decomposed by Fourier Series to estimate the wave load and ship motion transfer functions. These results show good correlation with predictions from model tests and potential flow calculations. From the computations, it is observed when increasing the wave length, wave diffraction around the ship becomes less profound and the water depth starts to influence the transfer functions. Full scale computations in head and oblique sea waves are also presented and compared with model scale predictions for investigating possible scale effects. The differences are found to be close to the numerical uncertainties, indicating minor influences of scale effects on the prediction of wave loads and ship motion responses for the tested cases. •URANS computations are performed on individual FLNG and LNG in waves.•Wave induced loads and motions are predicted for head and oblique sea conditions.•Simulation results are compared against potential flow solutions and model testing data.•Comparisons are made between model and full scale computational results.