The design process of mixers agitating non-Newtonian fluid flow is usually performed with several well-known correlation methods. These methods have been the issue of many studies of the last few decades, so they are well discovered and often extended. But these studies also disclose the dependency of the correlation methods on the rheology of the fluid flow. Due to the good applicability the discovered dependencies were often neglected. In this paper the existing methods will be investigated experimentally for agitating viscoelastic as well as viscoinelastic fluid flow to determine the influence of viscoelasticity on the power consumption of agitating non-Newtonian fluid flow. (C) 2016 Elsevier Ltd. All rights reserved.