Numerical study on maneuvering a container ship in shallow water waves

Abstract

Numerous practical and mathematical techniques have been piloted to study ships’ behavior in deep water conditions with and without waves, and shallow water conditions without waves, while only limited investigations have been carried out to assess ships’ behavior in shallow waters with wave conditions as the flow around the stern region and appendages and the interaction effects are intricate. Therefore, this study attempts to understand the infrequently explored subset of a vessel’s behavior in regular waves in shallow water conditions (channel depth to ship draft ratio taken as 1.5). A container ship (S175) model scaled at 1:36 was the subject of a numerical study in which it was subjected to static and dynamic maneuver simulations in head sea conditions. The waves were induced using the dispersion relationship of waves in a given depth. The trends of forces and moments acting on the hull while undergoing maneuvering motions were obtained using a smooth particle hydrodynamics-based computational fluid dynamics solver. The resulting periodic trends of forces and moments were analyzed using the Fourier series method to extract the Fourier coefficients and, in turn, calculate the hydrodynamic derivatives. The trajectories in turning circle and zigzag maneuvers were also simulated using a MATLAB code. The results demonstrate an increase in trajectory parameters and improvement in counter maneuverability owing to the complex flow physics around the hull when encountering regular waves in shallow water conditions compared to waves in deep waters and a lack of waves in shallow waters.