Research on propeller bearing force of a four-screw ship in oblique flow

Abstract

The present study conducted numerical simulations to investigate the influence of oblique flow on the bearing force performance of a four-screw ship, specifically analyzing the wake field and self-propulsion performance. The characteristics of the wake field and bearing force were compared and analyzed in detail under different drift angles (β=0°, ±10°, and ±20°). The findings suggest that the outside propeller wake field is more significantly impacted by a positive drift angle, whereas the effect is reversed for negative drift angles. Both the inside and outside propellers exhibited an increase in propeller axial average loads with an increase in drift angle. The drift angles were found to shift the location of the peak and trough of the single blade unsteady load due to the relative direction of propeller rotation and lateral incoming flow. Propeller loads with drift angles were observed to be larger than those under straight ahead conditions, with the amplitudes of the inside propeller at negative angles being greater than those at positive angles, likely due to the intense bilge vortex. Notably, the outside propeller demonstrated maximum amplitudes of axial loads at a β = 10° condition, while the minimum was observed at a β = −10° condition.