The Effect of Dilute Polymer Solutions on Viscous Drag and Turbulence Structure

摘要: All recent results confirm that the major differences between dilute polymer and Newtonian flows occur in an expanded buffer region near wall. The wall- normal velocity fluctuations decrease principal axes for Reynolds shear stress rotate toward streamwise wall-normal directions. Lower threshold uv events quadrants 2 4 are damped while higher not damped. mean period of burst cycle increases as drag reduction same way streak spacing increases. While wall-layer structures modified flows, they still contain all features structures.