Ship speed in pack ice

The pack ice field consists of individual ice floes separated by stretches of open water, as shown in the Figure 2.6.3. Ice floes have thickness equal to that of the level ice of the route.

　

Figure 2.6.3 Geometry of pack ice field showing track of ship

　

The floe size is given as probability distribution shown in the equation (2.6.12)similar to the situation of ridged ice.

　

　

where p(D) is a cumulative probability distribution function, D_m is a mean ice size. The equation(2.6.13)is used to calculate ice spacing.

　

　

where C is a total ice concentration, D is an ice size given in the equation(2.6.12). The resistance is obtained by the Lindqvist resistance formula. The ship speed can be estimated on the assumption of that the resistance in pack ice is equal to T_NET, in the equation (2.6.1). The ship speed is obtained as the distribution, hence the Pack ice calculation uses a probabilistic technique the same as the ridged ice calculation.

前ページ　　　目次へ　　　次ページ