界面活性剤水溶液の高Reynolds数Taylor-Couette乱流における平均流速分布

抄録

The relationship between the modulations of mean velocity and wall-frictional drag in high Reynolds-number Taylor-Couette turbulence by surfactant additive is experimentally investigated. Due to the viscoelasticity of a dilute surfactant solution, mean azimuthal velocity shows a non-monotonic profile in the radial direction accompanied by the drag enhancement for the co-rotation of the cylinders while such profile is not observed for the counter-rotation where the drag reduction occurs. In the non-monotonic velocity profile, a flow structure like solid-body rotation exists in a bulk region. Thus, the cause of the drag enhancement can be explained by considering that an additional angular momentum transfer is required to sustain this solid-body-like rotational flow although the generation mechanism of the mean flow structure is to be explored.