Numerical Modeling of Local Scour Around Cilindrical Piers Including Secondary Flows Effects

The aim of the present study is to provide a computational low-cost numerical model be able calculating the local scour around bridge piers at a temporal and spatial scale of the river. A mathematical model based on the shallow waters equations including a parameterization of effects of secondary flows is presented. This mathematical model was implemented in Open Telemac software by modifying its source code in order to build the numerical model. In order to perform the parameterization of effects of secondary flows present in the phenomenon, a three-dimensional modeling of the flow field and local scour was performed using sedFoam computational tool implemented in OpenFoam. To carry out the calibration and/or validation of the proposed model, a measurement campaign was carried out in the Roncador Bridge piers located on the Magdalena River at the height of the town of Magangue, Bolivar. The measurements consisted in obtaining velocity data, depth of the water sheet, bathymetries and grain size of the bed. Measurements of velocity and depth of the water sheet were obtained with an Acoustic Doppler Current Profiler (ADCP). The bathymetries were performed with an echo sounder and a sonar type deeper. The bed shear stresses that are generated around the pile along with the scour holes in equilibrium and the velocity fields modified by the proposed model are presented.