ABSTRACT
The balance of centrifugal acceleration and centripetal pressure gradient in a river bend causes the formation of a secondary flow superimposed to the primary flow. The secondary flow consists of a circular motion in the plane perpendicular to the primary flow direction. In the upper part of the water column, flow is directed toward the outer part of the bend and in the lower part it is directed towards the inner bend. This three-dimensional phenomenon is responsible, for instance, for the formation of point-bars. As such, it is of crucial importance to accurately predict secondary flow for correctly estimating morphodynamic changes in river bends. We propose two cases for testing fluvial hydrodynamic and morphodynamic modelling software. The first case is purely hydrodynamic and focuses on capturing secondary flow. The second case considers the morphodynamic equilibrium state before and after a river bend. We show that Delft3D-FM is able to capture the essential physical features of both cases.
