3D plunge pool scour with protection measures

Plunge pool scour phenomena are well-known for destructive action at the base of hydraulic structures. An experimental study was conducted at the Hydraulic Laboratory of the University of Pisa, Italy, to investigate the hydraulics of 3D plunge pool scour in presence of simple protection measures. The main geometrical scour hole parameters were investigated and various relationships are proposed for different flow conditions. These parameters include the maximum dynamic scour hole depth, the maximum scour hole width and the location of the scour hole initiation point. Equations for all these parameters are presented in terms of the basic scour variables including the jet densimetric Froude number, jet impact angle, tailwater elevation above the originally horizontal sediment bed level and the protection permeability and longitudinal positions of the protection. Moreover, a scour hole typology and relationships for the non-dimensional longitudinal scour hole profile in presence of the protection are also given.