Measuring non-extensitivity parameters in a turbulent Couette-Taylor flow

We investigate probability density functions of velocity differences at different distances r measured in a Couette-Taylor flow for a range of Reynolds numbers Re. There is good agreement with the predictions of a theoretical model based on non-extensive statistical mechanics (where the entropies are non-additive for independent subsystems). We extract the scale-dependent non-extensitivity parameter q(r, Re) from the laboratory data.