Analysis of added resistance and seakeeping responses in head sea conditions for low-speed full ships using URANS approach

Abstract

The KVLCC2 and its modified hull form were investigated in regular head waves using Unsteady Reynolds Averaged Navier–Stokes (URANS) methods. The modified KVLCC2 (named KWP-bow KVLCC2) is designed for reducing wave reflection from the bow. Firstly, the original KVLCC2 is studied for verification of the present code and methodology and the computed time history of total resistance and 2DOF motions (heave and pitch) for the selected two wave length conditions are directly compared with the results obtained from KRISO towing tank experiment under the identical condition. The predicted added resistance, heave and pitch motion RAOs show relatively good agreement with the experimental results. Secondly, the comparison of performance in waves between KVLCC2 and KWP-bow KVLCC2 is carried out. We confirmed that newly designed hull form shows better performances in all the range of wave length conditions through both the computation and the experiment. The present URANS method can capture the difference of performance in waves of the two hull forms without any special treatment for short wave length conditions. It can be identified that KWP-bow KVLCC2 gives about 8% of energy saving in sea state 5 condition.