A Consideration on the Energy of Secondary Flow Around the Ship Section

Abstract

The energy of secondary flow around the frame line, T_2, is calculated by making use of the slender-body theory on 21 model ships. It is found that T_2 has a peak on each half body of the ship and the value of the peak varies with the fullness of the half body. C_<DJ>=(T_2/2)/(1/2ρSV^2) is calculated when T_2 is equal to the mean value of the maximum T_2 for the fore body and the one for the aft body. Resistance tests are carried out on the model ships and their form factors are obtained to compare them with C_<DJ>. The results show that there is a clear relation between the form factor and C_<DJ> for the majority of these examples.