Development of facilities for Control of pack ice movement and their design method

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In this research project, we obtained the following results :a) The coefficient of shearing force separated form the component of form drag force is obtained. In the case of ice jam, the form drag force can be ignored when l/H (l : length of ice floes, H : ice thickness) is mare than 450 because it is lero than 1% of the shearing force.b) Through the observation at Saroma lagoon, when ice floes are completely trapped in the ice boom, apart of the fluid force acting on the ice floes is transmitted via the ice floes to the ice boom, and the remainder of the fluid force due to arching of the ice floes, act the fixed structures.c) Two typed of ice booms (sink and float type ice boom and overturning type ice boom) were developed in this project, and they were able to control the movement of ice floes.d) Traditional type ice boom and newly developed ice booms were able to control the movement of fragile ice.e) Flaw conditions were simulated for three different conditions : no freezing on lagoon, lagoon frozen over, and lagoon frozen over and ice jam at ice boom. When an ice jam forms, the flaw rate after one cycle decreases to 70% of that under the condition of ice-free surface. The ice jam seems to hinder water exchange.f) Accuracy the method of high accuracy numerical simulation for the three dimensional fluid motion was developed and the method was applied to the fluid motion near structure with sufficient accuracy.g) River flow derived from ground water was estimated from EMMA to predict NO3-N concentration in the river water in the agricultural region.