COMPARISON OF 2 HIDING FUNCTION FORMULATIONS FOR NONUNIFORM SEDIMENT TRANSPORT CALCULATIONS

The paper presents two hiding function formulations for use with van Rijn's sediment transport formula, In the first, the non-uniform critical shear stress for each size fraction is calculated using the Shields critical shear stress of the mean particle for that size fraction, In the second, the non-uniform critical shear stress for each size fraction is calculated using the Shields critical shear stress obtained for the sediments geometric mean, The behaviour of each of the hiding functions is evaluated by simulating non-equilibrium non-uniform sediment transport in experiments conducted at the University of Aberdeen. These show marked differences in the quality of predictions obtained from the hiding functions, From this evidence, it appears that hiding functions based on the critical shear stress of the geometric mean possesses advantages over the alternative formulation.