Compression of floating ice fields

The compression of ice fields made up of thin flees is central to the proce sses of ice jam formation in northern rivers, pressure ridge formation in n orthern seas, and the dynamics of ice fields in Arctic and Antarctic margin al seas. This work describes the results of computer simulations in which a floating layer of circular floes, confined in a rectangular channel, is co mpressed by a pusher plate moving at a constant speed. The accuracy of the simulations is assessed by comparison with a series of similar physical exp eriments performed in a refrigerated basin. Following this comparison, the computer model is used to perform an extensive series of simulations to exp lore the effect of variations in channel length and width, the ratio of fle e diameter to thickness, flee on flee friction coefficients, and the distri bution of flee diameters on the force required to compress the flees. The r esults show that reducing the aspect ratio of the flees or increasing the f riction coefficient increases the force needed to compress the flees. Both changes increase the force by changing the dominant failure mechanism in th e layer of flees from rafting to underturning. Increasing channel width red uced the compressive force (per unit channel width) by reducing the relativ e importance of frictional drag at the channel edges. Last, the results of a simulation using a distribution of flee diameters was indistinguishable f rom those of a simulation using flees with a single diameter equal to the a verage diameter of the distribution.