Weak mean turbulent flow of dilute polymer solution

We present an experimental, comparative study of the turbulent quantities of a weak mean turbulent flow in water and in a dilute polymer solution with an emphasis on phenomena at small scales. The experiment is performed by using a three-dimensional particle tracking velocimetry (3D-PTV) system. 3D-PTV allows to measure in a Lagrangian manner fields of velocity and velocity derivatives. An interpolation to the Eulerean grid allows to analyze properties of the mean flow and of the fluctuating velocity field, in addition to the small scale quantities such as vorticity, strain and their production terms. The comparison between the experimental results of the water and dilute polymer solution flows provides a direct observation of the influence of polymers on the mean, fluctuating and small scale properties.