Investigation of Vortex Feeding of Polymer Into the Turbulent Boundary Layer

Abstract

The results of the experimental studies of the efficiency of the method of vortex feeding of polymers developed by the authors are presented. The novelty of the device lies in the fact that when the polymer is fed into the boundary layer, the longitudinal velocity and the additional circumferential velocity are reported simultaneously. It has been established that with the introduction of polyethylene oxide solutions into the boundary layer of the model, using the proposed device, a reduction in hydrodynamic resistance by 60% and hydrodynamic noise up to 14 dB were obtained, which indicates the high efficiency of the proposed vortex feed device to reduce resistance and noise. The paper presents a physical model that shows that polymers affect directly the inner region of the boundary layer. This leads to a thickening of the viscous sublayer and a decrease in the intensity of vortex structures in it. As a result, the process of migration of vortices from the viscous sublayer to the outer region of the boundary layer slows down. All this reduces the turbulence of the boundary layer, thereby leading to a decrease in hydrodynamic resistance and noise.