Application of the morphological acceleration factor in fluvial hydraulics

The morphological acceleration factor (Morfac) has been widely used to speed-up morphodynamic simulations, mostly in coastal applications. The value of Morfac was generally set by trial and error and little theoretical background is available to identify an optimal value of Morfac for a given application and a target level of accuracy. In the present research, we generalize the few previous theoretical analyses regarding two main aspects. First, the range of the considered parameters (Froude number, relative roughness, transport rate …) has been considerably extended to cover typical values characterizing fluvial applications and not only coastal settings. Second, we show that the optimal value of Morfac depends greatly on the specific mathematical formulation of the flow model and on the flow regime.