Development of a Low Cost and Safe PIV for Mean Flow Velocity and Reynolds Stress Measurements

In this study, a white light particle image velocimetry (WL PIV) system which employs a light sheet generated with a flash was used. The system was developed in order to provide a cost-efficient and safe alternative to laser systems while keeping the accuracy limits required for hydraulic model tests. To investigate the accuracy of WL PIV method under different flow conditions, experiments were done at three different values of flow rates. Then the velocity vectors of each flow rate through the flume were calculated by means of cross-correlation of the two subsequent images. Flow velocity and Reynolds stress of each experiment were measured. The accuracy and integrity of the experiments were validated by comparison to the results which were obtained with empirical models of the mean velocity and Reynolds stress distribution in the boundary layer. Excellent agreement between the experimental and empirical results was observed. The whole flow field from the entrance of the experimental flume to its outlet was also modeled computationally using the Reynolds averaged Navier-Stokes equations and the k-e turbulence model of FLUENTTM code. It was found that the WL PIV measurements had a deviation of about ۰.۵ to ۱.۵% from the computational results which provides further evidence that WL PIV can be applied successfully in open channel flow analysis.

Keywords:

Flow Velocity , WL PIV , Reynolds Stress , Empirical Models , FLUENTTM Code