Physical modelling of avalanches using an aerosol cloud of powder materials

The problem of physically modelling snow avalanches with an aerosol cloud is considered. Using the simplest model of avalanche-body motion, the criteria of similarity for transit and deposit zones are written. The transit relations between model and natural scales for dynamic parameters of the avalanche body are established. On the basis of the similarity criteria, an approximate physical model of avalanches with an aerosol cloud is made using a mixture of ferromagnetic sawdust and aluminium dust. The setup allows us to start and stop the model avalanche during any stage of its motion and to model actual avalanches. A series of experiments was completed. It is shown that the basic mechanism of aerosol cloud generation for model avalanches is related to the hydraulic jump of fluid when a stormy flow changes to a calm one. A comparison of parameters for model and “home” avalanches (the vicinity of Elbrus) showed that the ratios of the sizes of dense and aerosol components and deposition zones of those avalanches are close to the geometric scale factor and the ratios of velocities, and durations of processes are close to the square root of this coefficient. The latter corresponds to modelling the process by Froude number.