The Specification of Shear Stresses in Estuary Models

Synopsis

The widespread use of a coefficient of eddy viscosity, Nz, to describe the vertical distribution of shear stress in estuary models may not be justified. The concept of shear stress has a more sound physical basis than Nz and offers more scope since stresses can be determined directly from measurements in estuaries. Above the constant stress layer at the bed, the stress can be considered to be made up of a boundary layer drag which decreases linearly with height and a variable internal stress associated with accelerations and density structure in the flow.