Numerical and field investigations of local bridge abutment scour and unsteady downstream river flow from a nearby hydropower plant

Abstract

The content of our research was as follows: 1) analysis of typical turbines regimes while switching them on and off and flow regimes downstream; 2) continuous long lasting measurement of water level in many cross-sections of the river under investigation downstream the hydropower plants; 3) numerical simulation and investigation of untypical turbines regimes while switching them on and off and flow regimes downstream with application software MIKE 21 in the same unsteady flow conditions in which field measurements were made; 4) evaluation of the accuracy of hydrodynamic modeling results and possibilities for their application in predicting the local bridge abutment scour. The obtained data on water level and flow rate dynamics downstream the Kaunas hydropower plants have been analysed. Numerical model was developed to simulate the scour at bridge abutment and was calibrated for the same unsteady flow conditions. The obtained accurate results can be used for local bridge abutment scour evaluation.