Abstract
Experimental investigation of the flow structure of modified viscoelastic drag-reduced channel flow by PIV.In order to modify the flow,water was dosed to the drag-reduced flow from the whole surface of the channel wall.The result shows that characteristic flow structure was observed.In the modified drag-reduced flow,drag reduction rate decreases,a quite strong peak of streamwise velocity fluctuation was obtained in the near-wall region and additional peak was also observed in the region away from the wall.Considering the results of Reynolds shear stress, this modified drag-reduced flow can be categorized three regimes from the channel wall on the boundary of the peak position of the streamwise velocity fluctuation.
