Using CFD Calculations To Improve Predictions Of Ship Manoeuvres

Manoeuvring simulation programs are generally based on empiric formulae derived from databases consisting of model test results obtained in the past. For novel ships or ships that lie outside the range of ship particulars covered by the database, the reliability of the prediction of the manoeuvring performance of ships can be questionable. Recent CFD developments provide the possibility to obtain more reliable manoeuvring estimates in the early design.
This paper presents the necessary steps required to predict ship manoeuvres using CFD tools as a Virtual Manoeuvring Basin. Based on a series of CFD calculations (including verification and validation of the results) in which captive model tests on the bare hull are mimicked, hydrodynamic coefficients are derived. These coefficients are fed into the simulation program and a series of standard manoeuvres is simulated and a sensitivity study is conducted. Comparisons between the original (fully empirics-based) predictions, the new predictions (improved by CFD) and free sailing manoeuvring test results are made. It is shown that considerably better predictions are obtained.