Validation of free surface vortex analytical models

During the last fifty years, several studies have been performed on free surface vortex formation and evolution, and different analytical models have been developed. In a previous work, three different models were analyzed and discussed to evaluate limits and strong points of each one. In this paper the same three models have been considered and compared with experimental results obtained for different horizontal planes by means of Particles Image Velocimetry technique. Mean velocity fields have been measured and discussed for each test case, highlighting the vortex flow field differences at different heights and flow rates. Experimental results have been compared with three analytical vortex models in terms of tangential velocity and vorticity profiles; two parameters needed by the models - the circulation and the vortex core radius - are derived from the experiments. Further considerations on the circulation distribution in axial and radial directions are included.