Stability of Floating Ice Blocks

The critical conditions at which buoyant blocks on a flowing stream are swept under a downstream floating cover are investigated analytically and experimentally. The mathematical model of block stability is based on a one-dimensional hydrodynamic analysis of the flow passing beneath the upstream end of a floating cover, and the force and moment equilibrium of the block. It is argued that the condition of incipient submergence is reached when the block sinks and rotates until the stagnation water surface elevation equals that of the top upstream edge of the block. Experiments to verify the analysis were conducted in a 1-ft wide laboratory flume using right parallelpiped blocks with three different specific gravities and a range of length-thickness ratios. The moment coefficient which arises in the analysis was evaluated by means of the experimental data, which were found to be in good agreement with the analytical results.