Abstract: Phase Doppler anemometry (PDA) was applied to the measuring of the turbulent char-acteristics of drag-reducing fluid, and the mean velocity profiles were gained. The relation be-tween the profile shape and the drag reduction ratio was discussed. The effects of the velocity fluctuations in normai direction on the drag reduction were investigated. The Reynolds stresses of drag-reducing fluid were contrasted with those of Newtonian fluid, which showed that the Reynolds shear stresses of drag-reducing fluid decreased drastically.

Key words: drag reducing fluid, surfactant solution, PDA