Numerical Study on the Scale Effects of the Ship Resistance and Form Factor

Abstract

The scale effects of form factor, wake field and resistance components are investigated by RANS method in this paper. DTMB5415, KCS and KVLCC2 with double-model flows and free-surface flows are studied at different scales. Considering the validation and verification, different grids and time step are used to calculate flows around ship at identical Reynolds number. Double-model flows of the three ships at different scales are calculated to study the scale effects of the viscous resistance components, form factors and wake field. The calculated viscous and friction resistance coefficients show a decreasing tendency against Reynolds number among all three ships. Viscous pressure resistance coefficient decreases with Reynolds number and obviously relies on hull form. Form factor shows a positive correlation with Reynolds number, moreover when above Re=109 it will converge to a constant value. The computed mean axial wake fractions decrease with increasing Reynolds number. On the other hand, the free-surface flows of the three ships at different scales are calculated to study scale effects of total and wave resistance. Total resistance coefficient decreases with an increasing Reynolds number, on the contrary, the wave resistance coefficient increases with an increasing Reynolds number.