Abstract
It is important from an engineering aspect to understand drag-reducing viscoelastic flow, since comprehension of the drag-reduction mechanism may facilitate designs with better additive types and/or channel configurations. In this study, we investigated the attenuation of vortices in fully-developed turbulence of viscoelastic fluid between parallel planes by DNS (Direct Numerical Simulation). We discussed how the viscoelastic stress plays a role in the reduction of the turbulent motions around eddies and how it influences the entire flow field. For determining the major effect of viscoelastic stress, we examined also 3 stage statistical data, with emphasis on the eddy evolution. We found that inhibition of turbulent eddies would be caused by the following aspects: the longitudinal eddy less occurs, the damping of eddies by viscoelastic stress occurs particularly in the ejection area, and the development of eddy is relaxed by the viscoelastic stress during the eddy growing stage.
