2-DIMENSIONAL MATHEMATICAL-MODELING OF LOCAL-SCOUR HOLES

A morphological model for the development of local-scour holes behind structures is developed, based on the 2-D Navier Stokes and convection -diffusion equations. The bed-load (transport) and the concentration a t a reference level close to the bed are prescribed using a stochastic al approach for the instantaneous bed shear-stress. The standard devia tion of the latter is closely related to the turbulence energy in the mixing layer and to the bed turbulence. The computed developments of l ocal-scour holes in scale models and in prototype are compared to meas ured developments. Reasonable results regarding flow velocities, sedim ent concentrations and bed configurations as function of time are obta ined, promising reliable predictions for local-scour holes in practice .