Vol 77 No 3 77314

Abstract

This study employs numerical simulations to analyse the flow field characteristics around the bow of a research vessel under drift angles of 0°, 10°, and 20°, as well as during turning motions. The investigation focuses on how different operating conditions influence the velocity, pressure, streamline distribution, and vortex structures. Results indicate that an increase in drift angle leads to more complex flow patterns and vortex evolution, which consequently intensifies hull rolling and turbulence, thereby affecting navigation stability. Variations in pressure gradients alter the streamline distribution along the hull surface, modifying ship forces and the surrounding flow, and contributing to bubble sweep-down near the bow. During turning motion, the flow field evolves through four sequential stages—straight sailing, yawing, deceleration, and steady rotation—each corresponding to distinct ship motion states and exhibiting clear stage-dependent changes in flow structure and hydrodynamic performance. The identified flow mechanisms, particularly the strong downwash and vortex dynamics under high drift angles, provide critical insights for assessing and mitigating acoustic interference risks for research vessels during complex manoeuvring operations.