Determination of the additional resistance that occurs during the ship’s motions in various confined waterways
The article defines the additional resistance that occurs in the case of ship's motions in shallow water, ship's motions parallel to the vertical wall in shallow water and during the motions in the channel. The additional resistance is determined based on the determination of the longitudinal component of the wave drift force according to the methods developed in previous works. These methods are based on the application of the method of integral equations and mirror images for cases of ship's motions parallel to the vertical wall and in the channel. The study carried out in domestic practice is new. The article presents the results of calculations of additional resistance arising during the motions of various types of ships in regular heading waves. A study is being made of the influence of various factors on their values, namely: changes in the relative depth of the fairway, changes in the distance between the ship and the vertical wall, changes in the relative width of the channel. A significant increase in the values of additional resistance with a decrease in the relative depth, a decrease in the relative width of the channel and the distance between the ship and the wall is shown. The values of the additional resistance are compared with the results of calculations performed using the approximate methods of Joosen and Gerritsma. The impossibility of using approximate methods in determining the additional resistance in the channel is shown.